&EPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-45O/2- 77-OO 1 b
April 1978
Air
Standards Support
and Environmental
Impact Statement
Volume 2:
Promulgated
Standards of
Performance for
Grain Elevator
Industry
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EPA-450/2-77-001b
STANDARDS SUPPORT
AND ENVIRONMENTAL
IMPACT STATEMENT
VOLUME 2:
PROMULGATED STANDARDS
OF P E R F 0 R M A N C E
FOR GRAIN ELEVATOR INDUSTRY
EMISSION STANDARDS AND ENGINEERING DIVISION
U, S, ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR AND WASTE MANAGEMENT
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
APRIL, 1978
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Thia report has been reviewed by the Emission Standards and Engineering Division, Office of Air
Quality Planning and Standards, Office of Air and Waste Management, Environmental Protection
Agency, and approved for publication. Mention of company or product names does not constitute
endorsement by EPA. Copies are available free of charge to Federal employees, current contractors
and grantees, and non-profit organizationsas supplies permitfrom the Library Services Office,
Environmental Protection Agency, Research Triangle Park, North Carolina 27711; or may be
obtained, for a fee, from the National Technical Information Service, 5285 Port Royal Road,
Springfield, Virginia 22161.
Publication No. EPA-450/2-77-001b
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FINAL
Standards Support and
Environmental Impact Statement:
Grain Elevators
Type of Action; Administrative
Prepared by
-tu
ULM^h^
\v_
Don R. Goodwin', Director
Emission Standards and Engineering Division
Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Date
Approved by
David G. Hawkins
Assistant Administrator
Office of Air and Waste Management
Environmental Protection Agency
401 M Street, S. W.
Washington, D. C. 20460
Date
Draft Statement Submitted to EPA's Office
of Federal Activities for Review on
Date
Additional copies may be obtained or reviewed at:
Environmental Protection Agency (PM-213)
Library (MD-35)
Research Triangle Park, North Carolina 27711-
Public Information Reference Unit
Room 2922
401 M Street, S. W.
Washington, D. C. 20460
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TABLE OF CONTENTS
Page
Chapter 1. SUMMARY.; 1-1
1.1 BACKGROUND " '. 1 -1
1.2 -SUMMARY OF CHANGES SINCE PROPOSAL '..... 1-2
.1.3 SUMMARY OF ENVIRONMENTAL IMPACTS... ''... . . 1-3
1.4 CHANGE IN ECONOMIC IMPACTS.. .. a...........^ 1-5
Chapter 2. SUMMARY OF PUBLIC COMMENTS .. , 2-1
2.1 NEED FOR STANDARDS. ., 2-1
2.2 EMISSION CONTROL TECHNOLOGY , 2-3
2.3 STRINGENCY OF THE STANDARDS .. 2-5
2. 4 OPACITY I 2-7
2.5 ECONOMIC AND ENERGY IMPACTS ......,!.. 2-10
2.6 MODIFICATION i .- 2-13
2.7 PERFORMANCE TEST ,! 2-18
2.8 SAFETY , 2-18
i
LIST OF TABLES
TABLE 1 ,! '.. 2-22
I
REFERENCES ! 2-24
APPENDICES
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APPENDIX I - OSHA HAZARD ALERT ! 1-1
.
APPENDIX II - NATIONAL FIRE CODE (NATIONAL FIRE I PROTECTION
ASSOCIATION) 1 II-l
APPENDIX III - FGIS INSTRUCTIONS i III-l
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1. SUMMARY
1.1 BACKGROUND
On January 13, 1977, standards of performance were proposed for
the grain elevator industry (42 FR 2842) under the authority of
j
section 111 of the Clean Air Act. Public comments were requested
on the proposal in the FEDERAL REGISTER publication. One thousand
eight hundred and seventeen comments were received from grain elevator
operators, vendors of equipment, Congressmen, State arid local air
pollution control agencies, other Federal agencies, and individual LI. S.
i
citizens. Many of these comments reflected a general misunderstanding
of the proposed standards and were very general in nature. A number of
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comments, however, contained a significant amount of useful data and
information. Due to the time required to review these comments, the
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standards were suspended on June 24, 1977. This action was necessary to
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avoid creating legal uncertainties for those grain elevator' operators
who might wish to undertake various expansions or modification projects
before promulgation of final standards. . i
On August 7, 1977, Congress amended the Clean Air Act. These
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amendments contained a provision specifically exempting country grain
elevators with less than 2.5 million bushels of grain storage capacity
from standards of performance developed under section 111 of the Act.
Following review of the public comments, a draft of the final
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standards was developed consistent with the adopted amendments to the
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Clean Air Act. A report responding to the major issues raised in the
public comments and containing the draft final standards was mailed on
August 15, 1977, to each individual, agriculture association, equipment
vendor, State and local government, and member of Congress who submitted
comments. Comments were requested on the draft final standards by
October 15, 1977. One hundred and one comments were received, and the
final standards reflect a thorough evaluation of these comments.
1.2 SUMMARY OF CHANGES SINCE PROPOSAL
1.2.1 Applicability of the Standards
The proposed standards v/ould have applied to all new, modified, or
reconstructed farm, country, and terminal grain .elevators with a receiving
leg capacity of more than 10,000 bushels per hour and all new, modified,
or reconstructed grain storage elevators at wheat flour mills, wet corn
mills, dry corn mills (human consumption), rice mills, or soybean oil
extraction plants. The promulgated standards apply only to new, modified,
or reconstructed grain elevators with a permanent grain storage capacity
of more than 2.5 million bushels and new, modified, or reconstructed
grain storage elevators at wheat flour mills, wet corn mills, dry" corn
mills (human consumption), rice mills, or soybean oil extraction plants
with a permanent grain storage capacity of more than 1 million bushels.
1.2.2 Emission Limits
As a result of information submitted during the public comment
periods, several changes have been made in the emission limits included
in the standards. The visible emission limits for truck unloading
stations and railcar loading and unloading stations have been increased
from 0 percent opacity to 5 percent opacity. The visible emission limit
for barge and ship loading has been increased from 10 percent opacity
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during normal loading and 15 percent opacity during ''topping off" loading,
to 20 percent opacity during all loading operations. ; The maximum allowable
hole size for perforated plates in column-dryers has been increased from
0.084 inch diameter to 0.094 inch diameter. .'.
-1.2.3 Modifications
Section 60.12 of the general provisions has beeil clarified to
.
ensure that only capital expenditures which are spent directly on
an affected facility are used-to determine whether the annual asset
guideline repair allowance percentage is exceeded, and the annual
asset guideline repair allowance percentage has been defined to be
~ ..
6.5 percent. Four types of alterations at grain elevators have been
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exempted from consideration as modifications. Table 1 summarizes the
changes to the regulation between proposal and promulgation.
1.3 SUMMARY-OF THE ENVIRONMENTAL IMPACTS ;-
1.3.1 Alternatives to the Promulgated Action
The alternative emission control systems which were considered in
selecting the basis for the promulgated' standards are discussed in
chapter 4 of Volume I of the Standards Support and Environmental Impact
Statement (SSEIS). These alternatives are based upon combinations of
various emission control techniques for reducing fugitive and process
emissions of particulate matter from grain elevators. An analysis, of
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the alternative of taking no-action or postponing action,'is outlined in
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chapter 7 of Volume I of the SSEIS. A number of the; emission limits
included in the proposed standards have been increased'. With the
exception of rail car unloading, however, these changes do not reflect
a change in the emission control systems upon which these limits are
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based but a revaluation of the ability of these emission control systems
to reduce emissions. The basis for the emission limits for railcar
unloading has been .changed from a shed with doors at each end to a shed
with open ends. This change will increase particulate emissions to the
atmosphere. The increase, however, is judged to be small and does not
significantly affect the analysis of the alternatives included in Volume I
of the SSEIS.
1.3.2 Environmental Impact of the Promulgated Action
Primary Impact
Several changes to the standards affect the primary impact of
reduction in emissions of particulate matter from grain elevators. .The
rationale for these changes is given in chapter 2 of this document. The
standards now apply only to large grain elevators. In addition, the
basis for the standards for railcar unloading has been changed and the
plate perforation hole diameter for column dryers has been increased.
These changes will result in more emissions of particulate matter to
the atmosphere and are primarily due to the change in applicability of
the standard which was mandated by the August, 1977 amendments to the
Clean Air Act. It was estimated that the proposed standards would
have resulted in reducing particulate matter emissions by approximately
23,000 tons within a 5 year period, it is now estimated that the
promulgated standards will reduce particulate matter emissions by 12,000
tons within a 5 year period.
Table 1-2 of Volume 1 of the SSEIS presents a summary of the
environmental impacts associated with implementation of the standards.
This matrix will not=significantly change as a result of these revisions
to the standards.
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Secondary Impact
Table 7-1 of Volume 1 of the SSEIS presents a summary-of the secondary
enviromental impacts attributable to the alternative control systems.
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These secondary impacts remain unchanged for the promulgated standards
of performance. ':
1.4 CHANGES IN ECONOMIC IMPACTS
In accordance with Executive Orders 11821 and 11949 and OMB Circular
A-107, the economic and inflationary impacts of each of the alternative
emission control systems were carefully evaluated. This analysis is
contained in chapter 6 of Volume 1 of the SSEIS. Since the changes made
to the proposed standards do not significantly affect the level of
emission control required for a large grain elevator, tH economic
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impact of the promulgated standards is essentially the same as that
outlined for the proposed standards for individual elevators. Since the
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scope of the promulgated standards has been narrowed, however, the
estimated national economic impact of the standards has been reduced as
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discussed in chapter 2 of this document.
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2. SUMMARY OF PUBLIC COMMENTS
Approximately 1800 comment letters were received on the proposed
standards of performance for grain elevators. Many of these comments
were the result of misinterpretation of the standards. A number of
comments, however, included a significant amount of data land informa-
i
tion. These comments were evaluated and draft final standards developed.
A report responding to the major issues raised in the public comments
and containing a copy of the draft final standards was sent to all
individuals and organizations who had expressed an interest in these
standards. A 60 day period was allowed for further comment on the draft
final standards and about 100 additional comment letters;were received.
The major public comments on the proposed and draft final standards
have been combined into the following areas for discussion:
(1) Meed for standards.
(2) Emission control technology. !
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(3) Stringency of the standards.
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(4) Opacity.
(5) Economic and energy impacts.
(6) Modifications.
(7) Performance tests.
(8) Safety.
2.1 NEED FOR STANDARDS ''
Numerous commenters questioned whether grain elevators should be
regulated since the industry is a small contributor to nationwide
emissions of particulate matter and grain dust is not hazardous or toxic.
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The standards were proposed under section 111 of the Clean Air Act.
This section of the Act requires that EPA establish standards of perfor-
mance for new stationary sources which contribute to air pollution.
Existing sources are not affected unless they are reconstructed or
modified in such a way as to increase emissions. The overriding purpose
of standards of performance is to prevent new air pollution problems
from developing by requiring maximum feasible control of emissions from
new,, modified, or reconstructed sources at the time of their construction.
This is helpful in attaining and maintaining the National Ambient Air
Quality Standard (MAAQS) for particulate mater.
The Report of the Committee on Public Works of the United States
Senate in September, 1970 (Senate Report No. 91-1196), listed grain
elevators as a source for which standards of performance should be
developed. In addition, a study of 200 industrial categories of
sources which were evaluated to develop a long-range plan for setting
standards of performance for particulate matter ranked grain elevators
relatively high. The categories were ranked in order of priority based
on potential decrease in emissions. Various grain handling operations
ranked as follows: grain processing-4; grain transfer-6; grain cleaning
and screening-8; and grain drying-33. Therefore, grain elevators are a
significant source of particulate matter emissions and standards of
performance have been developed for this source category.
Many commenters felt, however, that it was unreasonable to require
country and farm elevators to comply with the proposed standards because
of their remote location and small amount of emissions. This sentiment was
reflected in the 1977 amendments to the Clean Air Act which exempted
country elevators with a grain storage capacity of less than 2.5 million
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bushels from standards of performance. Consequently, the scope of the
proposed standards has been narrowed and the promulgated standards
apply only to new, modified, or reconstructed facilities within grain
*
elevators with a permanent storage capacity in excess of 2.5 million
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bushels.
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A number of commenters also felt small flour mills should not-be
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covered by standards of performance because they are also small sources
of particulate matter emissions and handle less grain than some country
elevators which were exempted from standards of performance by the 1977
amendments to the Clean Air Act. These processors are considered to
be relatively small sources of particulate matter emissions that are
best regulated by State and local regulations. Consequently, grain
storage elevators at wheat flour mills, wet corn mills, dry corn mills
(human consumption), rice mills, and soybean oil extraction plants
with a storage capacity of less than 35,200 m3 (ca. 1 million
U. S. bushels) of grain are exempt from the promulgated standards.
With regard to the hazardous nature or toxicity of grain dust,
"
the promulgated standards should not be interpreted to imply that
.grain dust is considered hazardous or toxic, but merely that the
grain elevator industry is considered a significant source of
particulate matter emissions. Studies indicate that, as a general
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class, particulate matter causes adverse health and welfare effects.
In addition, some studies indicate that dust from grain elevators
causes adverse health effects to elevator workers and that grain dust
' emissions are a factor contributing to an increased incidence of asthma
attacks in the general population living in the vicinity of grain elevators.
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2.2 EMISSION CONTROL TECHNOLOGY
A number of commenters were concerned with the control technology used
to control emissions from railcar unloading stations and grain dryers.
A number of commenters believed it was unreasonable to base the
standards on a four-sided shed for railcar unloading stations at grain
elevators which use unit trains. The data supporting the proposed standards
were based on observations of visible emissions at a grain elevator
which used a four-sided shed to unload railcars. This grain elevator,
however, did not use unit trains. Based on information included in a
number of comments, the lower rail rate for grain shipped by unit trains
places a limit on the amount of time a grain elevator can hold the unit
train. The additional time required to uncouple and to recouple each
car individually could cause a grain elevator subject to the proposed
standards to exceed this time limit and thus lose the cost benefit
gained by the use of unit trains,. In light of this fact, the proposed
visible emission limit based on the use of a four-sided shed for railcar
unloading is unreasonable. The promulgated standards, therefore, are
based upon the use of a two-sided shed for railcar unloading stations.
This change in the control technology for rail car unloading stations
resulted in a change to the opacity standard which is discussed in a
subsequent section in this chapter.
A number of comments were received concerning the specification
of the maximum hole size in the perforated plates used in column dryers.
The proposed standards would have permitted holes no larger than 2.1 mm
(0.084 inch) in diameter for the dryer to automatically be in compliance.
A few comments contained visible emission data taken by certified opacity
observers which indicated that column dryers with perforated plates
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containing holes of 2.4 mm (0.094 inch) diameter can meet a 0 percent
/opacity emission limit. Other comments indicated that sorghum cannot
be dried in column dryers with a hole size smaller than 2.4 mm (0.094
-inch) diameter without plugging problems. In light of these data and
information, the specification of 2.1, mm diameter holes |is considered
.unreasonable and the promulgated standards permit perforated plates with
a maximum hole size of 2.4 mm diameter.
2.3 STRINGENCY OF THE STANDARDS
Many commenters questioned whether the standards for various affected
facilities could be achieved even--if the best system of emission reduction
were installed, maintained, and properly operated. These commenters
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pointed out that a number of variables can affect the opacity of visible
emissions during unloading, handling, and loading of grain and they
questioned whether enough opacity observations had beenjtaken to assure
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that the standards could be attained under all operating conditions.
The variables mentioned most frequently were wind speed, type of grain,
dustiness of grain, and moisture content of grain.
It is true that wind speed could have some effect on the opacity
of visible emissions, particularly when sheds .have only two sides.. A
well-designed capture system should be able to compensate for this effect
to a certain extent, although some dust may escape if Wind speed is too
high. Compliance with standards of performance, however, is determined
only under conditions representative of normal operation, and judgment
" by State and Federal enforcement personnel will take wind conditions
into account in enforcing the standards.
It is also true that the type of grain, dustiness of grain, and
moisture content of grain affect the amount of particulate matter
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emissions generated during unloading, handling, and loading of grain. A
well-designed capture system, however, should be designed to capture this
dust under adverse conditions and should, therefore, be able to compensate
for these variables.
In developing the data base for the proposed standards, over 60
plant visits were made to grain terminal and storage elevators. Various
grain unloading, handling, and loading operations were inspected under a
wide variety of conditions. Consequently, the standards were not based
on conjecture or surmise, but on observations of visible emissions by
certified opacity observers at well-controlled existing grain elevators
operating under routine conditions. Not all grain elevators were visited,
however, and not all operations within grain elevators were inspected
under all conditions. Thus, while the proposed standards were based
upon a sufficiently broad data base to allow extrapolation of the data,
particular attention was paid to those comments which included visible
emission data taken by certified observers from operations at,grain
elevators which were using the same emission control systems the proposed
standards were based upon. Evaluation of these data indicated that the
visible emission limit for truck unloading station and railcar loading
stations should be 5 percent opacity instead of 0 percent opacity which
was proposed. The promulgated standards, therefore, limit visible
emissions from these facilities to 5 percent opacity.
As discussed earlier, the emission control technology selected as
the basis for the visible emission standard for railcar unloading has
been changed from a four-sided shed to a two-sided shed. Visible
emission data included with the comments indicate that emissions
from such a system will not exceed 5 percent opacity. Consequently, the
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promulgated standards limit visible emissions from railcar stations to
5 percent opacity. ,
A number of commenters also indicated that the opacity limit
included in the proposed standards for barge loading was too stringent.
One commenter indicated that the elevator operator had no control over
when the "topping .off" operation commenced because the ship captain and
the stevedores decided when to start "topping off." Several State .agencies
commented that the standards should be at least 20 percent opacity. Based
on these comments, the standards for barge and ship loacling operations
have been increased to 20 percent opacity during all loading operations.
The comments indicate that this standard will still require use of the
i
same emission control technology.
Data included with the comments confirm that a visible emission limit
,
of 0 percent opacity is appropriate for grain handling equipment, grain
dryers, and emission control equipment. Consequently, the visible
emission limits for these affected facilities have not been changed.
2.4 OPACITY i
Many commenters misunderstood the concept of opacity and how it is
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used to measure visible emissions. Other commenters stated that opacity
measurements were not accurate below 10 to 15 percent opacity and a standard
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below these levels was unenforceable.
Opacity is a measure of the degree to which particulate matter or other
visible emissions reduce the transmission of light and obscure the view of
an object in the background. Opacity is expressed on a scale of
0 to 100 percent with a totally opaque plume assigned a value of
100 percent opacity. The concept of opacity has been used in the field
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of air pollution control since the turn of the century. The concept
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has been upheld in courts throughout the country as a reasonable and
effective means of measuring visible emissions.
Opacity for purpose of determining compliance with the standard
is not determined with instruments but is determined by a qualified .
observer following a specific procedure. Studies have demonstrated
that certified observers can accurately determine the opacity of
visible emissions. To become certified, an individual must be trained
and must pass an examination demonstrating his ability to accurately
assign opacity levels to visible emissions. To remain certified, this
training must be repeated every six months.
In accordance with Method 9, the procedure followed in making
opacity determinations requires that an observer be located in a
position where he has a clear view of the emission source with the
sun at his back. Instantaneous opacity observations are recorded
every 15 seconds for 6 minutes (24 observations). These observations
are recorded in 5 percent increments (i.e., 0, 5, 10, etc.). The
arithmetic average of the 24 observations, rounded off to the nearest
whole number (i.e., 0.4 would be rounded off to 0), is the value of
the opacity used for determining compliance with visible emission
standards. Consequently, a 0 percent opacity standard does not
necessarily mean there are no visible emissions. It means either
that visible emissions during a 6 minute period are not sufficient to
cause a certified observer to record them as 5 percent opacity, or that
the average of the twenty-four 15.-second observations is calculated to
be less than 0.5 percent. Consequently, although emissions released
into the atmosphere from an emission source may be visible to a certified
observer, the source may still be found in compliance with a 0 percent
opacity standard. . .
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Similarly, a 5 percent opacity standard permits visible emissions
to exceed 5 percent opacity occasionally. If, for example, a certified
observer recorded the following twenty-four 15-second'observations over
a 6 minute period: 7 observations at 0 percent opacity; 11 observa-
tions at 5 percent opacity; 3 observations at 10 percent opacity; and
3 observations at 15 percent opacity, the average opacity would be
calculated as 5.4 percent. This value would be rounded off to
5 percent opacity and the source would be in compliance with a .
5 percent opacity standard.
None of the standards are J>ased on a single six-rninute reading of
opacity. .Each of the standards are based on the highest opacity readings
recorded over a period of time, such as two or four hours, at a number
of grain elevators. In addition, opacity standards are never enforced
on the basis of a single six-minute reading. A number of opacity readings
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are made before an enforcement action is initiated.
A number of commenters also felt the opacity standards were too
stringent in light of the maximum absolute error of 7.5 percent opacity
associated with a single opacity observation. The methodology used to
develop and enforce opacity standards, however, takes into account this
observer error. As^discussed above, opacity standards are based on
observations recorded by certified observers at well-controlled existing
facilities operating under normal conditions. When feasible, such
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observations are made under conditions which yield the highest opacity
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readings such as the use of a highly contrasting background. These
readings then serve as the basis for establishing the standards. By
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relying on the highest observations, the standards inherently reflect
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the highest positive error introduced by the observers.
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Observer error is also taken into account in enforcement of visible
emission standards. A number of observations are normally made before
an enforcement action is initiated. Statistically, as the number of
observations increases, the error associated with these observations
taken as a group decreases. Thus, while the absolute positive error
associated with a single opacity observation may be 7.5 percent, the error
associated with a number of opacity observations, taken to form the basis
for an-enforcement action, may be considerably less than 7.5 percent.
2.5 ECONOMIC AND ENERGY IMPACTS
2.5.1 Economic Impact
Several comments indicated that the estimated economic impact of the
proposed standards was too low. Some commenters questioned the ventilation
flow rate volumes used in developing these estimates. The air evacuation
flow rates and equipment costs used in estimating the costs associated
with the standards, however, were based on information obtained from
grain elevator operators during visits to facilities which were being
operated with visible emissions meeting the proposed standards. These
air evacuation flow rates and equipment costs were also checked against
equipment vendor estimates and found to be in reasonable agreement. These
ventilation flow rates, therefore, are compatible with the opacity
standards. Thus, the unit cost estimates developed for the proposed
standards are considered reasonably accurate.
Many commenters felt that the total cost required to reduce emissions
to the levels necessary to comply with the opacity standards should be
assigned to the standards. The relevant costs, however, are those
incremental costs required to comply with these standards above the costs
required to comply with existing State or local air pollution regulations.
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While it is true that some States have no regulations, other States have
regulations as stringent as the promulgated .standards. Consequently, an
estimate of the costs required to comply, with the typical or average
State regulation, which lies between these extremes, is subtracted from
the total cost of complying with the standards to identify the cost
impact directly associated with these standards. !
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Most State and local regulations, for example, require aspiration
of truck dump pit grates and installation of cyclones to remove particu-
late matter from the aspirated air before release to the atmosphere. The
promulgated standards would require the addition of a bi-fold door and
!
the use of a fabric filter baghouse instead of a cyclone. ' The cost
associated with the promulgated standards, therefore, is ^nly the cost
of the bi-fold doors and the difference in cost between a ;fabric filter
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baghouse and a cyclone.
In conclusion, the unit cost estimates developed for the proposed
standards are essentially correct and generally reflect the costs associated
with the promulgated standards. As a result, the economic impact of the
promulgated standards on an individual grain elevator is considered to be
about the same as that of the proposed standards. The maximum additional
cost that would be imposed on most grain elevators subject to compliance
with the promulgated standards would probably be less than a cent per
bushel. The impact of these additional costs imposed on an individual
grain elevator would be small. |
Based on information contained in comments submitted by the National
Grain and Feed Association, approximately 200 grain terminal elevators
and grain storage elevators at grain processing plants would be covered
by the standards over the next five years. Consequently,!over this five
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year period the total incremental costs to control emissions at these
grain elevators to comply with the promulgated standards, above the
costs to control emissions at these elevators to comply with State or
local air pollution control requirements, is $15 million increased,capital.
costs over a five year period and $3 million in increased annualized
costs in the fifth year. Based on this estimate of the national economic
impacts the promulgated standards would have no significant effect on
the supply and demand of grain or grain products, or on the growth of
the domestic grain industry.
2.5.2 Energy Impact ,
A number of commenters believed that the energy impact associated
with the proposed standards had been underestimated and that the true
impact would be much greater. As pointed out above, the major reason
for this disagreement is probably due to the fact that these commenters
assigned the full impact of air pollution control to the proposed
standards, whereas the impact associated with compliance with existing
State and local air pollution control requirements should be subtracted.
In the example discussed above concerning costs, the additional energy
requirement associated with the promulgated standards is simply the
difference in energy required to operate a fabric filter baghouse
compared to a cyclone.
For emission control equipment such as cyclones and fabric filter
baghouses, energy consumption is directly proportional to the pressure
drop across the equipment. It was assumed that the pressure drop
across a cyclone required to comply with existing State and local
requirements would be about 80 percent of that across a fabric filter
baghouse required to comply with the promulgated standards. This is
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equivalent to an increase in the energy consumption required to operate
air pollution control equipment, of about 25 percent. This only represents
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an increase of less than 5 percent in the total energy consumption
required to operate a grain elevator. j
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Assuming 200 grain elevators become subject to the promulgated
standards over the next five years, this energy impact will increase
national energy consumption by less than 10,000 barrels per year in .
1982. This amounts to less than 2 percent of the capacity of a large
marine-going oil tanker and is only a small increase in energy
consumption.
2.6 MODIFICATION
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Many commenters were under the mistaken impression that all
existing grain elevators would have to comply with the proposed
standards and that retrofit of air pollution control equipment on
existing facilities within grain elevators would be required. This
is not the case. The proposed standards would have applied only to
new, modified, or reconstructed facilities within grain elevators.
Similarly, promulgated standards apply only to new, modified, or
reconstructed facilities and not existing facilities.
Modified facilities are only subject to the standards if the modi-
fication results in increased emissions to the atmosphere from that
I
facility. Furthermore, any alteration which is considered routine
maintenance or repair is not considered a modification. Where an altera-
tion is considered a modification, only those facilities which are
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modified have to comply with the standards, not the entire grain elevator.
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Consequently, the standards apply only to major alterations of individual
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facilities at existing grain elevators which result in Increased emissions
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to the atmosphere, not to alterations which are considered routine
maintenance and repair. Major alterations that do not result in
increased emissions, such as an alteration where existing air
pollution control equipment is upgraded to maintain emissions at
their previous level, are not considered modifications.
The following examples illustrate how the promulgated standards
apply to a grain elevator under various circumstances. The proposed
standards would have applied in the same way.
(1) If a completely new grain elevator were built, all of the
affected facilities would be subject to the standards.
(2) If a truck unloading station at an existing grain elevator were
modified by making a capital expenditure to increase unloading capacity
and this resulted in increased emissions to the atmosphere in terms of
pounds per hour, then only that affected facility (i.e., the modified
truck unloading station) would be subject to the standards. The remaining
facilities within the grain elevator would not be subject to the standards.
(3) If a grain elevator contained three grain dryers and one grain
dryer were replaced with a new grain dryer, only the new grain dryer would
be subject to the standards.
The initial assessment of the potential for modification of existing
facilities concluded that few modifications would occur. The few modifi-
cations that were considered likely to take place would involve primarily
the upgrading of existing country grain elevators into high throughput
grain elevator terminals. A large number of commenters, however, indicated
that they believed many modifications would occur and that many existing
grain elevators would be required to comply with the standards.
2-14
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To resolve this confusion and clarify the meaning of modification, a
meeting was held with representatives of the grain elevator industry to
identify various alterations, to existing facilities that might be considered
modifications. A list of alterations was developed which frequently
i
occur within grain elevators, primarily to reduce labor costs or to
increase grain handling capacity, although not necessarily annual grain
throughput. The impact of considering four of these alterations as
modifications, subject to compliance with the standards, was viewed as
unreasonable. Consequently, they are exempted from consideration as
modifications in the promulgated standards.
i
In particular, the four alterations within grain elevators which
are specifically exempt from the promulgated standards are (1) the
addition of gravity load-out spouts to existing grain storage or
grain transfer bins; (2) the addition of electronic automatic grain
weighing scales which increases hourly grain handling capacity;
(3) the replacement of motors and drive trains driving existing grain
handling equipment with larger motors and drive trains which increases
hourly grain handling capacity; and (4) the addition of grain storage
capacity with no increase in hourly grain handling capacity.
If the first alteration were considered a modification, this could
require installation of a load-out shed thereby requiring substantial
i
reinforcement of the grain storage or grain transfer bin to support the
weight of emission control equipment. In light of the relatively small
expenditure usually required to install additional gravity load-out
.
spouts to existing grain storage or transfer bins, and the relatively
'
large expenditure that would be required to install a load--out shed
or to reinforce the storage or transfer bin, consideration of this
2-15
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sort of alteration within an existing grain elevator as a modification
was viewed as unreasonable.
Under the general modification regulation which applies to all
standards of performance, alteration two, the addition of electronic
automatic grain weighing scales, would be considered a change in the
method of operation of the affected facility if it were to increase
the hourly grain throughput. If this alteration were to increase
emissions to the atmosphere and require a capital expenditure, the
grain receiving or loading station whose method of operation had
changed (i.e., increased grain throughput) would be considered a
modified facility subject to the standards. Consideration of this
type of alteration, which would result in only minor changes to a
facility, is viewed as unreasonable in light of the relatively high
expenditure this could require for existing grain elevators to
comply with the standards.
Alterations three and four, replacement of existing motors and
drives with larger motors and drives and addition of grain storage
capacity with no increase in the hourly grain handling capacity,
would probably not be considered modifications under the general
modification regulation. Since it is quite evident that there was
considerable confusion concerning modifications, however, alterations
three and four, along with alterations one and two discussed above,
are specifically exempt from consideration as modifications in the
promulgated standards.
The modification provisions in 40 CFR 60.14(e) exempt certain
physical or operational changes from being considered as modifications,
even though an increase in emission rate occurs^ Under 40..CFR 60.14(e)(2),
2-16
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if an increase in production rate of an existing facility can be accom-
plished without a capital expenditure on the stationary source containing
that facility, the change is not considered a modification.
A capital expenditure is defined as any amount of money exceeding
i
the product of the Internal Revenue Service (IRS) "annual asset guideline
repair allowance percentage" times the basis of the facility, as defined
by section" 1012 of'the"Internal Revenue Code. In the case of grain
elevators, the IRS has not listed an annual asset guideline repair
allowance percentage. Following discussions with the I'RS, the Department
of Agriculture, and the grain elevator industry, the Agency^deternrined
that 6.5 percent is the appropriate percentage for the grain elevator
industry. If the capital expenditures required to increase the
production rate of an existing facility do not exceed the amount
calculated under the IRS formula, the change in the facility is not
considered a modification. If the expenditures exceed the calculated
amount, the change in operation is considered a modification and the
'
facility must comply with MSPS.
Often a physical or operational change to an existing facility
to increase production rate will result in an increase in the
production rate of another existing facility, even though it did not
undergo a physical or operational change. For example, if new
i
electronic weighing scales were added to a truck unloading station
to increase grain receipts, the production rate and emission rate
would increase at the unloading station. This could result in an
increase in production rate and emission rate at other existing
facilities (e.g., grain handling operations) even though physical
or operational changes did not occur. Under the present wording of
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the regulation, expenditures made throughout a grain elevator to adjust
for increased production rate would have to be considered in determining
if a capital expenditure had been made on each facility whose operation
is altered by the production increase. If the capital expenditure made
on the truck unloading station were considered to be made on each existing
facility which increased its production rate, it is possible that the
alterations on each such facility would qualify as modifications. Each,
facility would, therefore, have to meet the applicable NSPS.
Such a result is inconsistent with the intent of the regulation.
The Agency intended that only capital expenditures made for the changed
facility are to be considered in determining if the change is a modifi-
cation. Related expenditures on other existing facilities are not
to be considered in the calculation. To clarify the regulation, the
phrase "the stationary source containing" is being deleted. Because
this is a clarification of intent and not a change in policy, the
amendment is being promulgated as a final regulation without prior
proposal.
2.7 PERFORMANCE TEST
Several commenters were concerned about the costs of conducting
performance tests on fabric filter baghouses. These commenters stated
that the costs involved might be a very substantial portion of the
costs of the fabric filter baghouse itself, and several baghouses may
be used at a moderately sized grain elevator. The commenters suggested
that a fabric filter baghouse should be assumed to be in compliance
without a performance test if it was properly sized. In addition, the
opacity standards could be used to demonstrate compliance.
2-18
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It would not be wise to waive performance tests in all cases.
Section 60.8(b) already provides that a performance test may be waived if
j
"the owner or operator of a source has demonstrated by other means to
the Administrator's satisfaction that the affected facility is in compliance
i
I
with the standard." Since performance tests are heavily weighed in court
proceedings, performance test requirements must be retained to ensure
effective enforcement. j
2.8 SAFETY
-'' - - I
In December, 1977, and January, 1978, several grain elevators exploded.
These explosions were caused by a combination of fuel (grain dust is
mainly organic), oxygen, and a source of ignition (such as; an open
flame, static electric spark, hot bearing, etc.). Several allegations
were made by various individuals within the grain elevator industry contending
that Federal air pollution control regulations are contributing to an increase
i
in the risk of dust explosions at grain elevators by requiring that building
doors and windows be closed and by concentrating the dust
in emission
control systems. Investigation of these allegations indicates that they are false.
There are no Federal regulations specifically limiting dust emissions
from grain elevators which were in effect at the time of these grain
elevator explosions. A number of State and local air pollution control
agencies, however, have adopted regulations which limit particulate
matter emissions from grain elevators. Many of these regulations were
developed by States and included in their implementation plans for
attaining and maintaining the MAAQS for particulate matter. Particulate
matter, as a general class, can cause adverse health effects; and
- ' - "i .
the NAAQS, which were promulgated by EPA on April 30, 1971, were
established at levels necessary to protect the public health and welfare.
2-19
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Although compliance with-State or local air pollution control
regulations, or the promulgated standards of performance, can be achieved
in some instances by closing building doors and windows, this is not the
objective of these regulations and is not an acceptable means of compliance-
with these regulations. The objective of State and local regulations and
the promulgated standards of performance is that dust be captured at these
points within grain elevators where it is generated through the use of
effective hoods or enclosures with air aspiration, and removed from the
building to an air pollution control device. This is the basis for the
promulgated standards of performance. Compliance with air pollution control
regulations and the promulgated standards of performance does not require
that windows and doors in buildings be closed to prevent escape of dust and
this practice may in fact be a major safety hazard.
Fabric filter baghouses have been used for many years to collect
combustible dusts such as wheat flour. There have been extremely few
incidences of dust explosions or fires caused by such emission control
devices in the flour industry. In the grain elevator industry, no a-ir
pollution control device has been identified as the cause of a grain
elevator explosion. Consequently, fabric filter baghouses, or emission
control devices in general, which are properly designed, operated, and
maintained do not contribute to dust explosions at grain elevators.
These conclusions were supported at a joint meeting on December 29,
1977, between representatives of EPA; the Federal Grain Inspection -
Service (F6IS) of the Department of Agriculture; the Occupational Safety
and Health Administration (OSHA); the grain elevator industry; and the
fire insurance industry. Installation and use of properly designed,
operated, and maintained air pollution control systems were found to be
2-20
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consistent with State and local air pollution regulations, OSHA regu-
lations, and national fire codes. Chapter 6 of the National Fire Code
for Grain Elevators and Bulk Grain Handling Facilities (NFPA No. 61-B),
which was prepared by the National Fire Protection Association, for
example, recommends that "Dust shall be collected at all" dust producing
points within the processing facilities." The code then goes on to
specially recommend that all elevator boots, automatic scales, scale
hoppers, belt loaders, belt discharges, trippers, and discharge heads,
and all machinery such as cleaners, scalpers, and similar devices be
provided with enclosures or dust hoods and air aspiration.
Consequently, compliance with existing State or local air pollution
regulations, or the promulgated standards of performance, will not increase
the risk of dust explosions at grain elevators if the approach taken to
meet these regulations is capture and control of dust at. those points
within an elevator where it is generated. If, however, the approach taken
I
is merely to close doors, windows, and other openings to trap dust within
the grain elevator, or the air pollution control equipment is allowed to
deteriorate to the point where it is no longer effective in capturing dust
as it is generated, then ambient concentrations of dust within the elevator
I
will increase and the risk of explosion will also increase.
The House Subcommittee on Compensation, Health, and Safety is
currently conducting oversight hearings to determine if something needs
to be done to prevent these disastrous grain elevator explosions. The
FGIS, EPA, and OSHA testified at these oversight hearings on January 24
and 25, 1978. The testimony indicated that dust should be captured and
collected in control devices in order to reduce the incidence of dust.
explosions at grain elevators, protect the health of employees from such
2-21
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ailments as "Farmer's Lung," and prevent air pollution. Consequently,
properly operated and maintained air pollution control equipment will
not increase the risk of grain elevator explosions.
OSHA issued a hazard alert in January, 1978, concerning dust explosions _
at grain elevators. -This hazard alert is included in Appendix I. The FGIS
also issued safety guidelines in January, 1978, for determining whether a grain
elevator is safe for an FGIS grain inspector to work in. These guidelines
are included' in Appendix II. The National Fire Protection Association
guidelines which pertain to grain elevators are included in Appendix III.
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Table 1
(A) Applicability
Proposed Standard
Farm elevators country elevators, grain
elevator terminals, and commercial rice
dryers, with a total receiving leg
capacity of more than 10,000 bushels
per hour which handle or process wheat,
corn, milo.rice, rye, oats, barley, or
soybeans.
Promulgated Standard
Grain elevator terminals (i.e., grain
elevators which have permanent
grain storage capacity of over
2.5 million bushels which handle or
process wheat, corn, sorghum, rice,
rye, oats,; barley, or soybeans.
Grain storage elevators at wheat flour
mills, wet corn mills, dry corn mills
(human consumption), rice mills, and
soybean oil extraction plants, which handle.
or process wheat, corn, milo, rice, rye,
oats, barley, or soybeans.
2.
Grain storage elevators at-wheat flour mills,
wet corn mills, dry corn mills (human consump-
tion), rice mills, and soybean oil extraction
plants, which handle or process wheat, corn,
sorghum, rice, rye, oats, barley, or soybeans
and which ,iave a grain storage capacity of
over 1 million bushels.
(B) Limits of Standard
and Basis
.Affected Facility
1. Fugitive Emissions
A. Truck loading
8. Truck unloading
C. Bo'xcar' and hopper
car loading
D. Boxcar and hopper
,car unloading
Emission Limit
10% opacity
0% opacity
0% opacity
No visible
emissions
Basis*
Two-sided shed with one
end open, the other
fitted with doors.
Ventilation of loading
spout to control device.
Two-sided shed with one
end open, the other fitted
with doors. Ventilation of
receiving hopper to control
device.
Two-sided shed with ventila-
tion of loading spout to
control Device.
Four-sided shed, both ends
fitted with doors. Ventila-
tion of receiving hopper to
control device.
Emission Limit
Same as proposed
5% opacity
52 opacity
5% opacity
Basis*
Same as proposed
Same as proposed
Same as proposed
Two-sided shed, both ends
open. Ventilation of
receiving hopper to
control device.
2-23
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Affected Facility
£. Barge or ship
loading
F. Barge or ship
unloading
Proposed Standard
Emission Limit
lOt opacity loading
15S opacity topping-off
Equipment standard
G. Grain dryer
01 opacity or equip-
ment standard
H. Grain handling OS opacity and 0.01
2. Emission Control
Device on Air
Ventl Hated
frorc Affected
Facilities
(C) Modification
All modifications were covered.
Of: opacity and 0.01
grain per dry
stanasrd cubic foot
Table 1 (continued)
Basis*
Choke feed with loading"
ventilated to control
device.
Marine leg enclosed
from top to bottom of -
leg, with ventilation-
.flow rate of both leg
, and receiving hopper"
of 40 cubic feet of air
per bushel of grain
unloaded.
1. Column dryer - use
perforated plates '
with hole sizes no
larger than- 0.084,
inch diameter.'
2. Rack dryer - use of
50 mesh or ffner
screen.
Enclosed and ventilated
legs, scales, trippers,
and transfer points.
Fabric filter baghouse
Promulgated Standard
Emission Limit
Basis*
20?: for all loading Same as proposed
operations
Same as proposed ' Same as, proposed
Same as proposed
Same as proposed
Same as proposed
1. Column dryer -', use of
perforated plates with
hole sizes, no.larger
than o:.094 inch
diameter,
2. Rack dryer - same as
proposed.
Same as proposed
Same as proposed
1. Modification does not cover the following:
A.- The addition of gravity load-out spouts
to existing grain storage transfer Mns.
B. The installation of automatic grain
weighing scales. '
C. Replacement of motor and drive units
driving existing grain handling equipment.
D. Th'e installation of storage capacity with
no increase in hourly grain handlinp
capacity.
2. Lists the "annual asset guideline repair
allowance,''...percentage, at 6.5%.
3. Only apply expenditures to an affected facility
in determining whether a capital expenditure has
been made.
*The standard does not mandate the use os specific equipment indicatea as "basis." Any equipment meeting the emission
I1HU or any equipment that is shown to be eouivalent in controlling paniculate matter is acceptable.
2-24
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REFERENCES
I
1. "Standards Support and Environmental Impact Statement - Volume I:
Proposed Standards of Performance for Grain Elevator Industry",
U. S. Environmental Protection Agency - OAQPS,; EPA-450/2-77-001a,
Research Triangle Park, North Carolina, January, 1977.
2. "Draft - For Review Only: Evaluation of Public Comments: Standards
of Performance For Grain Elevators" U. S. Environmental Protection
Agency - OAQPS, Research Triangle Park, North Carolina, August, 1977.
3. "Standards Support and Environmental Impact Statement - Volume II:
Promulgated Standards of Performance for Grain Elevator Industry",
U. S. Environmental Protection Agency - OAQPS,; EPA-450/2-77-001b,
i
Research Triangle Park, North Carolina, April, 1978.
2-25
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APPENDIX I
-------
-------
U.S. DEPARTMENT OF LABOR. .
Occupational Safcfy zsd Health Adrainiscrstior.
WASHIXG7CN, D.C 20210
Office of the Assistant Secretary
Dear Employer:. ' " ' - _
-Within the past month grain elevator explosions in Louisiana, Texas,
Illinois, and Mississippi have taken the lives of -more, than 50 people.
An additional fifty or more workers have been hospitalized for Injuries
Suffered in these incidents. In- an effort to prevent other deaths and
injuries, I am issuing the enclosed Grain Elevator Hazard Alert and
.urging employers to take immediate actions to safeguard their employees,
The enclosed material describes the nature of grain elevator hazards, .
"steps that can be taken, the role of Federal and State Job. safety and
health officials, and sources of assistance available to employers"
seeking to protect their employees. -..- ;
The central purpose of this Grain Elevator Hazard Alert is to provide
employers, workers, and public officials with available information
concerning grain elevator safety hazards in hopes of eliminating the
kinds of dangers that result in explosions. In addition, however, we
are providing information concerning health hazards associated with
storage and distribution of grain. Some of these hazards involve .
worker exposure to excessive grain dust, the use of toxic fumigants,
and possible worker contact with silica.
It is my strong recocmendation-that grain elevator operators carefully
"read and follow the requirements and recommendations contained in this
hazard alert. Workers lives may literally depend upon your taking
appropriate action. " OSHA will, "of course, continue to "Inspect ".grain "
elevators to ensure compliance with applicable standards as -well as
the employer's general 'duty to furnish a workplace free from recog-
nized hazards causing or likely to cause death or serious harm to
workers. ' . :+....'
L. ....
OSHA is working closely with the U.S. Department of Agriculture's
Federal Grain Inspection Service, which has lost a number of employees
in these explosions, the Environmental Protection Agency, the Food and
Drug Administration and State and local officials to Discover the
causes of the recent explosions. As further 'information becomes
available it shall be made public. |
1-1
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's
'I ask your'support-in using the enclosed material to protect the lives
of the workers in this industry.-
Sincerely,
Bingham
Assistant Secretary '
Occupational Safety and H«
rth
Enclosure
1-2
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GRAIN ELEVATOR INDUSTRY
HAZARD ALERT
Prepared by the j
Occupational Safety and Health Administration
Dr. Eula Binghani i
i
Assistant Secretay of Labor \
January 5, 1978
1-3
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GRAIN ELEVATOR HAZARD ALERT
January 1978
I INTRODUCTION: During the recent Christmas season major explosions occurred
in qrain handling facilities, killing fifty people and injuring many othersv ;
These traqic events have made it imperative that employers take immediate action
to protect their employees and others present in such facilities. This Grain
Elevator Hazard Alert is designed to assist employers in meeting their respon-
sibilities by highlighting certain pertinent requirements and recommendations
regarding hazards in this"industry and their abatement.
This alert is based upon existing OSHA standards, applicable industry
consensus standards, and information obtained in recent consultations among
industry, government, and academic experts. As discussed below, compliance
with OSHA standards is mandatory for employers subject to the provisions of
the Occupational Safety and Health Act. The other elements of this Alert
are offered as guidelines which employers are urged to assess and adapt to
their operations. (Note: Under OSHA approved State Plans, state promulgated
standards may replace Federal standards. In general, the provisions of these
state standards will be similar to the Federal standards, and employers opera-
ting in such States are urged to comply with applicable State standards and
regulations.)
This alert contains information about both safety and health hazards.
Although the immediate concern is eliminating conditions that might cause
explosions, serious health hazards such as grain dust and toxic substances
also exist in grain elevators and may, over the long-run, cause many more
deaths than result from the kind of dramatic catastrophes that recently
occurred. Thus, considerable information is included concerning hazards to
workers and their abatement; further information on such health hazards may
be provided at a later date.
OSHA is providing this Alert to employers, workers, certain public
officials, and members of the general public concerned about this Problem.
In addition to approximately 10,000 grain elevators in the Urn ted States
the Alert is being sent to unions representing workers in the industry, all
OSHA Area Offices, the U. S. Department of Agriculture ^ Federal Gran
Inspection Service, other interested Federal agencies, stat* °«uf *
safety and health officials, States providing on-site co"sultatrve serv ces
to employers through contracts with OSHA, numerous colleges and universities,
and anyone requesting copies of the document.
Investigations of the recent explosions by OSHA and other governmental
agencies are underway but may not be complete for several weeks. The results
of those investigations will be made public and may be-the subject of a
second Alert if the findings so warrant.
1-4
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1
II., EMPLOYER RESPONSIBILITY:
The Occupational Safety and Health Act of 1970 requires employers to
furnish each employee a place of employment free from recognized hazards
likely to cause death or serious physical harm. Employers are al so mandated
to comply with occupational safety and health standards promulgated under
the Act. - i.
In later sections of this Alert, certain safety and jhealth hazards
associated with grain elevators are discussed and detailed requirements and
recommendations are presented. Employers are required to comply with the speci-
fic standards and are urged to comply with the recommendations that apply to
their operations. OSHA also strongly recommends, "however-, that compliance on
these matters be but a part of a comprehensive safety anci health program designed
by each employer for each of his facilities.
Guidance on the overall design of comprehensive safety and health programs
is available from a variety of sources, some of which are discussed-below.
Because of the nature of the hazards in this industry, OSHA recommends that
-special attention be given by grain elevator operators to the following matters
in setting up such a program: " i
1. Preventive Maintenance: . '.
i
i
A preventive maintenance program is a vital part of an overall grain
elevator safety and health program. Written, established and implemented pro-
cedures for regular inspections of al1- mechanical and electrical machinery and
equipment is strongly recommended. Standard operating procedures (SOP)^should
be established and conveyed to all employees affected regarding lockout and
tagout procedures when machinery is down for repair or replacement.
2. Housekeeping: Housekeeping, as discussed in detail in later
sections, is especially important in facilities where combustibles and the
danger of their explosion is present. Written and enforced SOP's are needed
to ensure adequate housekeeping. - '
3. Training: The need for training is never ending. All new
employees should be made aware of the company or co-op policies and operating
rules, especially the established safety and health procedures. Refresher
training of experienced employees in the hazards "of the job is important. -
Employees should be informed of their rights under-the Occupational
Safety and Health Act. i;
SOP's and frequent drills are needed for fire alerts, for evacuation
procedures due to bomb threats or fire, for emergency treatment (first aid)
cases.
1-5
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4. Outside Contractors: Special attention must be devoted to outside
contractors hired to enter and perform work in a grain elevator. While con-
tractors, as employers themselves, are obliged to provide their employees with
safe working conditions, grain elevator operators are urged to ensure that
contractors and their employees understand the hazards of the .grain^elevator
environment and company safety and health rules. Uninformed or careless contrac-
tors may be more likely to violate basic safety procedures, such as not using
explosion proof electrical tools or welding in unsafe environments.
5. Liaison with local safety agencies: Elevator operators should
be in close contact with fire and rescue agencies and other appropriate local
agencies that may assist in cases of emergency or that can provide advice and
assistance in'identifying and abating hazards. Employees should be trained
in the means of contacting fire and rescue agencies under emergency conditions.
6. Health Hazard Control: Because of the nature of the hazards in
the industry, preplacement physicals for all new employees are strongly advised,
including determinations of susceptibility of allergic reactions to commonly
encountered materials in grain elevator operations. Active monitoring of
potential health hazards is necessary on a periodic basis so as to maintain
good control of the environment.
The company policy implementing the program cannot by itself work the
necessary results for a safe and healthful work environment; it requires the
cooperation of all levels of management and employees, insurance and government.
Good communications is necessary among the various parties for any program to
be successful.
There are a number of sources of advice and assistance to employers
in meeting their general and specific obligations. OSHA Area Offices, located
in every State, will provide employers advice on-locating and correcting .
workplace hazards, either over the telephone or at the Area Office. States
operating their own occupational safety and health programs will provide
similar off-site advice. A list of relevant State agencies is attached.
In addition, thirty-nine States provide on-site consultation, in which
State employees visit the worksite and point out hazards and methods or
correction, where possible, without applying citations or penalties. This
service is provided upon request by employers, with preference given to small
business employers. (A list of these States is attached). OSHA's General
Industry Standards are available at all Federal or State OSHA offices. Also
available there are copies of the National Electric Code, the NFPA consensus
standards (NFPA 61-B, 57, 77) and certain publications concerning grain
elevators. An Iowa State University publication entitled, Literature Survey
of Dust Explosions in Grain Handling Facilities: Causes and Prevention
(March, 1976), is an extremely useful source book. Local offices of the
federal Grain Inspectionservice and EPA can also hel p employers with some
facets of the grain elevator work enviornment. ; .
1-6
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HI. Explosion and Fire Hazards
A. The Anatomy of an Explosion
widinq n,ayAVcPapabf]rof
cloud of dispersed dust const
dust5""?" SUCf »? an Cheated bearina or
8'" burai'n °f »
?
described visually as similar to dens^fog
B* MaJ°r Fire Hazards in Grain Elevators.
concentration can be
" wrkPl«« ^Utty present a
-9te 3 m1xed grain
r i9nition of a
firl^ard^AsTn a
dust layer at about one-haT f t etemprlu
grain dust cloud. Dust layer ; will
--layer .ill senerat/neat^
within the^ela'or* 'ihfslltli?! ^ ^^""9 and Iconveying locations
it is carried o?fb; a neffil ?«n? i st co^cMn'^0"?"0^ the Slevat0r unless
used with grain contain some flammable const tueSt? ^,irh t J°K fui^ants
ethylene dichloride, and (in the case of AfumS DH S-c Vaj;bon ^sulfide,
table two for the flammable properties 1 ^3fM' See
C* Maj'or F1re Iqni'tion Sources in Grain Elevator's.
1.
2.
3.
Open flames such as lighters, matches, Darning cigarettes
Slipping belts on bucket elevators and other conveyors.
Hot surfaces including light Dulbs, hot bearinqs
electrical appliances, slipping V-Delts.
paris °
1-7
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5. Electric sparks generated during operation of switches, fuses
blowing, damage to cables or equipment.
6. Static electricity.
7. Welding, cutting, soldering.
8. Spontaneous ignition in grain storage bins.
9. Lowering portable lamps into bins.
Although the ignition sources for the majority of grain elevator dust
explosion experiences in the United States since 1958 are unknown, the principal
known ones are welding and torch cutting operations together with hot surfaces
caused by friction, slipping belts, and smoldering fires. The actual recorded
causes of grain elevator explosions for the period 1958 through 1975, expressed
as a percentage of the total, are as follows:
Cause ' Percent
Unknown 62.0%
Welding-Cutting 10.2%
Friction 8.8%
Fire or Flame 8.0%
Electrical Equipment 6.6%
Lightning 2.9%
Spontaneous Combustion 1.5%
Source: Literature Survey of Dust Explosions in Grain Handling
Facilities: Causes and Prevention (Iowa State University, March 1976)
It is generally believed that the bucket elevator is the location in
the grain elevator complex in which fires most frequently occur. Some causes
being slipping belts, tramp metal, overheated bearings, metal buckets scraping
nearby surfaces, and static generation. Grain driers, which are located adjacent
to the grain elevator, also have a significant number of fires.
D. Required and Recommended Control Procedures for Fuel Sources.
1. Maintenance
The need for a comprehensive maintenance program is the single most
important aspect of a program for controlling fuel and ignition sources. Main-
tenance via good housekeeping practices in removing dust accumlation and through
keeping mechanical and electrical equipment in good running condition is essential
During grain handling operations, dust accumulations should be removed daily.
If the elevator is working 24 hours a day, then removal may be necessary several
times each day.
1-8
-------
_ _ _ In removing dust accumulations the creation of airborne dust should
be minimized. -The use of approved vacuum cleaners, is the preferred method.
practice of sweeping a work level, allowing 'the dust to drop to the next
1 Dust Collection System
in the contrn/nf H,^016??^ the dUSt Co11ection .system is an important factor
r' .St?te a9encies concerned with dust emissions, EPA and
th Hraln ^fP60*10" Serv1ce (FGIS) are all concerned with the
an ,,c i , ^ collection system. OSHA has a twofold interest in a
good dust collection system. First, the system can be used to minimize the amount
of dust_which represents an inhalation hazard; second, it can be effective in
minimizing the dust accumulations which are one recognized source of fire hazards
Present indications are that most existing systems use only single stage (fabrk
elevator. Collect1on with subsequent return of the collected material to the
her 1Q77 Il? ^ |;xp1°rato!7 technical meeting held by EPA and OSHA on Decem-
ber 30, 1977, in Washington, D.C. , OSHA was made aware of some preliminary
findings regarding a two stage filtering system. The initial stage is a cyclone
bark tnetSrSith%1aTr.fartiCleS Uh°Se W1'th Skater mass) and Returns them
SJccoJ t Jhelevat°I^ facillt^ The "ghter and smaller dust particles are then
passed to the second stage filter and removed by a fabric filter. The reported
method removes particle sizes of 20 microns or less. A portion of these small
particulars constitutes a respirable dust hazard. The present practice of u\ L
single-stage collection systems dictates the return of all co'llecCd particle °
back into the elevator. This practice of repetitively handling small Peculates
produces a dryer concentrated collection of small particulars that are morp
easily ignitable. Not only does this practice increase their ignUion sensHivitv
but by putting the particulates back into the elevator the hea th hazards
E'
and Recommended Control Procedures, for Ignition Sources
1 Bucket Elevator
(a) To minimize fire in the area of the bucket el<
evator the following
operating condition of
1-9
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(b) A belt slippage indicating device that can be seen from the operator's
station should be installed on bucket elevators.
(c) An audible alarm should be installed to activate when the speed of
elevator falls to 80-95% of its normal operating speed.
the
(d) A system shutdown sequence with the following steps should be used:
Upon activation of the audible alarm, the feed belt conveyors would be auto-
matically shut down; a time delay should be established which permits operation
of the bucket elevator but prevents the ignition or separation of the belt. The
time delay should not exceed the time required for the bucket elevator to clear
itself of grain or for the individual closest to the elevator to respond to the
alarm. The audible alarm should continue throughout the time delay. The bucket
elevator should shut down automatically following the termination delay.
(e)'Tramp metal collectors are recommended to remove at least the ferrous
materials. Depending on the volume of grain handled, the operator should esta-
blish a regular schedule for cleaning off the collected metals from the magnets.
When replacing a bucket elevator belt it should be replaced with a conducting
belt (to minimize static electrical charge) of low flammability and with
nonmetal buckets.
2. Grain Driers.
Although grain driers are usually located separately from grain
elevators, there have been numerous fires in grain driers. The following
precautions are based on the recommendations contained in NFPA 61-B:
(a) Driers should be constructed of noncombustible material.
(b) Expansion joints should be provided to prevent damage from
expansion or contraction.
(c) The primary intake air of the burners should be screened to prevent
foreign material from entering.
(d) Driers designed to recirculate a portion of the exhaust air should
employ a means of removing combustible particulate material from the air in
the recirculation duct.
(e) In a direct-fired drier using oil or solid fuels, a target plate or
other effective means should be used to prevent burning materials from enter-
ing the drying chamber.
(f) The interior surfaces of driers should be designed to facilitate
cleaning.
(g) Access doors or openings should be provided to permit inspection,
cleaning, and maintenance, and also to permit effective use of extinguishing ,
equipment in all parts of the driers and the connecting spouts or conveyors.
(h) Means should be provided to rapidly unload (dump) the drier to a safe
area in case of fire.
1-10
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(i) Drying processes conducted in buildings which 'are likely to contain
combustible dust should have heating devices and blowers located in a separate
dust-tight room or area. Such rooms or areas should not communicate with por-
tions of a building subject to dust. Surfaces of structural members and all
other objects in the area should be designed to reduce ;to a minimum any
accumulation of dust.
(j) Automatic means should be provided the drier and its auxiliary equip-
ment in order that it will shut-down the fuel supply in the event of a fire or
the development of excessive heat within the drier.
(k) A maximum temperature thermostat should be located between the
heat-producing device and the drier. Also, driers should have a thermostat
to control induced air temperatures inside the drying compartment.
i
(1) Extraneous material which contributes to the Hazard of the drying
operation should be removed from the product prior to entering the drier.
(m) Driers processing material containing vegetable oils should have
the accumulation of oil film removed from dryer surfaces to prevent the forma-
tion of an adhesive or combustible surface.
3. Welding and Cutting Operations. '
Welding and cutting operations require some special consideration. The
present OSHA welding and cutting standards have application to locations where
combustible dust is present. These operations have beem the source of ignition
for a number of explosions in grain elevators. Those welding contractors who
are hired to come into the elevator to make repairs or perform maintenance
work must be informed of the company regulations and of the hazards of the work
location. The contractors should ensure that their employees are informed.
The preferred way is to remove the object to be welded ,to an outside location
away from the elevator. Where this cannot be done,then all dust accumulations
and other fire hazards (fuel sources) in the vicinity shall be removed. Whenever
floor or wall openings exist through which sparks or slag might drop, precautions
should be taken to prevent this occurrence. For grain elevator operations a
fire watch person is necessary for almost all welding and cutting operations.
The fire watch person must be equipped and trained in the use of portable fire
extinguishers and the hazards of the location. The use of the written welding
permit system administered by the grain elevator operator is highly recommended
by OSHA as a control against unauthorized welding and cuting. OSHA. prohibits
welding or cutting in those areas where dust accumulations are present or
equipment is operating causing dust to be present. Conveyor equipment should
be shut down that is adjacent to the welding or cutting operations.
1-11
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4. Electrical Machinery and Equipmnt .
EJu1Pne"t Called in hazardous dust locations shall not permit arcs
or heat otherwise generated or liberated inside of the equipment or
equipment enclosure, to cause iqnition of exterior accumulations or Sospheric
suspensions of agricultural dust on or in the vicinity of the equipment or
equipment enclosure. Equipment so installed shall be able to function at full
ratio, jnthout develop!,, surface temperatures hiqh enough to cause excessive
n ^ ^ " carho»>'^ion of any agricultural dust deposits that
Operators shall use
only electrical
htch
motors, switches
on
sion 2 l
ei
shall be
maximum
fuse boxes
BOo'and
in either
As in the case with all electrical equipment to be used in hazardous
lT' £? ' g*n?rat0rs an? other rotatinq electrical machinery must
d for Division 1 locations (basically dust clouds the .ninimum
1:^ent^U?ns continually, intermittently, or periodically) and Divi-
ocations (basically dust in hazardous layers). In Division 1 locations
rrK 9Hd °ther.:?tat1^ electrical machinery shall l,e approved for
_be dust-ignition-proof or totally enclosed pine- von til afc»d. In
A 1°c?tl?n?' motors, generators and other rotating electrical machinery
dust-igniti on-proof or totally enclosed pipe-ventilated for which
surface temperatures shall not exceed 120° C (248° F) 'AH motors
0 8leCfcrica1 '^i^ shall i>e in accordance with OSHA
(b) In areas where lightning disturbances have been known to occur
'7Jy-e'^ ln ^"rdous dust locations shall be, when supplied from'
ead i.ne-i, suitably protected against high-voltaqe surges. This pro-
tection shall include suitable lightning protects devn'ces, interconnection
ot all grounds, and surge-protective capacitors. Employers shall i)royi-i°
NEc'°502-39 and SUrflS V°ltaqe Protection ^ accordance with OSHA 1910.309,
nnrnn chn Automatic j,,,,rnO dlar,n systans, approved for the
purpose, should be used to warn aqainst overheated bearings or other hot
spots on electric motors belts, pulleys, or wherever locations are suscep-
s.?
1-12
-------
Static electricity can sometimes become the ignition source for an
explosive concentration of agricultural dust. The accumulation of such static
Charges shall he prevented by adequately grounding or bonding in accordance
4ith the practices outlined in NFPA No. 77-1972. Any ground or bond that is
installed in accordance with OSHA 1910.309 NEC 50.2-3 and 502-16 for. lightning
protection or power circuits, respectively, shall be adequate for protection
of the same electrical equipment against static electricity,
(f) Where the installation of transmitting or receiving antennas on the
top of grain elevators cannot be avoided, all antenna masts and metal support
structures shall be permanently and effectively grounded and the co-iplete
assembly installed in accordance with OSHA 1910.309, NEC 810 and 820.
(g) Only power tools approved for the hazardous location, and which do
not present the danger of inadvertent ignition from electrical arcs or sparks,
shall be used in accordance v
-------
ci +'' Ft S" - C ] 1910'309- Th1s section references the 1971 National
Electrical Code. Art.lcle 500 (Hazardous locations) and Article 502 (Class
II Locations) would be applicable. These requirements concern electrical
wiring and equipment in environments containinq dust.
2. Section 1910.252. This section contains requirements nerMi:if.n
t.) --/elding, cutting, and brazinq. The requirements concerning "Fire oreven-
tion and Prohibited areas" would be apolicable to qrain elevators.
3. _ Section 1910.36 and 1Q10.37. These sections pertain to means of
eqrees WHICH .-tre necessary for employee emerqenc.y escape.
4. Section 1310.68 which contains requirements for manlifts.
5. Sections 1910.132, .133, .135, and .136 which address .-wrsonal pro-
tective equipment.
6. Section 1910.151 which contains medical and first-aid provisions!
7. Sections 1910.157, .158, .159, and 160 which address fire protection
requirements.
8. Section 1910.212 which contains req.n>ements for machine and machine
ouardinq.
9. Section 1910.242 and .244 which address hand and portable oower tools.
10. The General Duty Clause of the OSHA Act (Section 5(a)(D). Each
employer is required to furnish employment ind a place of employment which are
free from recognize-1 hazards that are causina or are likely to cause death or-
serious physical harm to his employees. The general requirement covers a number
of serious hazards not covered by OSHA standards. Nationally recognized consen-
sus standards may be used to support citation of the general duty clause'.'" "A'n ""
example of a consensus standaVd which could be used is:"'"Grain Flevators and
Sulk Grain Handling Facilities" (MFPA - 61-B). "
IV. Occupational Health Considerations and Guidelines
Commonly recognized health hazards for grain elevator employees..-ira.- "
known via certain signs and symptoms associated with these illnesses.
Symptoms following exposure to che-nicdl hazards, such as fumigants and
pesticides, include coughing, dizziness and tremors. The presence of red
blood cells in the urine is a "possible si oh of" over-exposure to"thes"e ' "
chemical hazards. Contact dermatitis nay develop with repeated exposure
to irritant effects of some pesticides. Working with qrain can also
result in a oarasite-caused dermatitis known as qrain itch. The arain lite
is the causative agent in this skin .condition.
i-xnosure to qrain dust may cause an acute allerqic reaction known «
grain fever. The symptoms of qrain fever are chills wi to'T?i-h::'-i", fever,
ohysical discomfort, gastric upset, sneezing, ind sore throat lasting 24
to 48 hours. The symotoms can r^our after especially heavy exposures or
after exposure ?.illowinq a week or more awav from the dust.
-ITT 14-
-------
Farmer s lung is another allergic respiratory disease which can be
triggered by the inhalation of almost any organic dust, whose particles
are smaller than 5 microns and thus able to penetrate to the periphery
or the lung. Tn general, the most common cause of this allergic reaction
is the inhalation of spores from moldy grain or hay. Symptoms include
breatnlessness, chills, fever, and cough which occur several hours followinq
the initial exposure to the dust. Dyspnea (difficulty in breathing) may ~
be so extreme as to be dssocUte-1 vith cyanosis (blue discoloration of the
skin due to oxygen deficiency). Weight loss may be pronounced. With
repeated exoosures emphysema may result. In addition to the inhalation
eJSrdS 21 Sases vapors, silica and grain dust, there are fumigant constituents,
such as those listed in Table 2, that can be absorbed through the skin. TWe
is some evidence that Ethylene Dibromide ("D3) may cause sterility. EDB, has
also been found to be carcinogenic in two aninal species and one target organ
the stoinacn. In spite of the presently existing standard of 20ppm for an 8 hour
time-weighted average, a revaluation of data suggests that, at present, a safe
exposure limit for ^33 has not been established. "Therefore, in the absence of
any data to suggest d safe level, exposure to airborne concentrations should b*
ivniv.M ta tne lowest-possible concentration, and skin contact should be avoided.
Carbon disulfide, carbon tetrachloride and phosphiiie also are present in
the work environment and should be evaluated to limit exposures to the threshold
limit values prescribed by OSHA.
,".., ' i '
Because of the lack of specific information on certain labels, employers
-should request a hazard data sheet from the manufacturer on each fumigant used
Employees should be trained to recognize the hazards of their jobs and should be
monitored for exposure to contaminants. (See Fiaure 1 for locations of poten-
tial employee monitoring.)
Mandatory exposure limits for hazardous substances including grain dust
(classified as an inert or nuisance dust) are found in Subpart Z Part 1910 of
the OSHA General Industry Standards. Table 2 contains a list of some substances
commonly found in grain elevators with Threshold Limit Values.
The practice o* inerting storage facilities using fumigants, requires
,,nucn stricter supervision and more stringent safety and health practices.
Any employee entering such areas should wear positive pressure self-con-
tained breathing apparatus, be secured by a properly anchored safety belt
lifeline, and have at least one fellow employee stationed outside the
hazardous area as an observer unless appropriate ventilation and monitoring of
the area for contaminants (Table 2} and oxygen is undertaken prior to entry.
The observer should be capable of providing rescue services and should be '
equipped with similar personal protective equipment. The use of breathing
apparatus or respirators requires training of employees to wear the equipment
properly. OSHA Program Directive 300-9 and standards 29 CFR 1910.134 provide
details on the requirements for use of respirators by employees.
1-15
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TABLE I
MAJOR COMPONENTS OF SOME G4/UM -~:.HI G
Trade Name
Inaredients
Weevil-Cide (Weevil-Cide Co.)
Diamond Premium Brand Fumiaant
Serafume (now-Chem)
i! 'Ciller (Farmland)
Phostoitin (Heqesch Chem Co.)
Hetia
Carbon tetrachloride (skin) 78.81/,
Carbon bisulfide , .....--19.7%
Sulfur dioxide ,..,-., J~ - ; 1.5%
Carbon tetrachloride (skip:) 17.R%
Carbon disal fide ; 19.2%
Sulfur dioxide , 1.0%
Petroleum ether 1.0%
Carbon tetrachloride (skin) 76.5%
Ethyleoe dichloride , 10..0%
Carbon bisulfide 10.0%
Ethylene dihrvynid*.1 (;kiO l.W
Ethylene dichloride 64.6%
Carbon tetnie'il orM^ (skin)- ?7.4"4
"t'nyl ene di bromide (skin) 5.0%
Sulfur dioxide 3.0%
Aluminum phosphide 55.0%
Inert ingredient 45.0%
A.ltmiinun1 phosphide
Inert " -
1-16
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Substance
TABLE 2
Hazardous Substances Commonly
Encountered in Grain El^-Hir Ti^
Threshold Limit Value Or Permissible
2-Butannne (MEK) '
Carbon monoxide
Carbon tetrvt-'il .>"' ii 'j'-cin)
Carbon disulfide .
Ethyl ene H'-jroiiMe (skin)
Ethyl ene di chloride
Methane!
Phosphine
Sulfur dioxide
".nert or M'lisan:-? dust (e.i.
Respirable fraction
total
Exposure Level s
p.p.m. mq/m3
200 590
50 55
10
20
20
50
200 260
0.3 0.4
5 13
arain dust)
5
15
: Max. * LKL.
Ceilina Value
i
' ''' '"1?-
200 p.p.m. MA
loo p.p.m. inne
MA
200 2
!50 NA
6
Danqeri).is
'n/i.-'i
i
NOTFJ: These -1ata are excerpted from Tables Z-l, Z-2 and Z-|3 in the
J.VU.MM'! ''-njatry H'M ) 1i-M> '/hich are currently in effect.
LEL = Lower Explosive :. i v"
1-17
-------
To iisjra thdt e-n;>l #.-*»; .^i n': :>:|.-ied under grain »vhen working in
is, emoloyees should -il-n '>* 'Tii.ooed with a safety belt lifeline,'and have an
server .j-2Si.it. r.i.)l.v/.^.;.; unVoTlM-i -Kii i r^w should be notified of the
"k to be done before it start*. T.) t'-i-j :-ise oF bins with movable or selective
Jtribution systems, the turnheads, spouts and trinper should be locked out
)»i those areas in which employees are working. Additionally, in-those bins
th fixed distribution or fill snouts, a similar practice should be emnloyed.
Regulations concerning eating areas, general sanitation facilities and
rrain control are also covered by OSHA standards i.i ?.3 Z-R 1920.141; these*
quirements must be complied with.
This general information should be used to identify and eliminate grain
evator health hazards.
I-L8
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APPENDIX II
-------
-------
UNITED*STATES DEPARTMENT OF AGRICULTURE . .
Federal Grain Inspection Service
1400 ladqpendence Avenue, SW ; .
Washington, D.C. 20250 '
i
=- " - *
INFORMATION FOR'AND ACTION BY: All FGIS Employees, Chief Grain Inspectors,
and Grain Industry Plant Management
INSTRUCTION 370-3
.
Alert Guideline Procedures 'and 'Policies upon Encountering "Hazardous
/';. .'Conditions" in Grain Elevators'
"
PURPOSE
This Instruction.:
'
. .
A Sets forth -procedures^ and policies when major safety violations are
encountered by employees~5"f" the Federal Grain Inspection Service, (FGIS) while
performing official duty in grain, rice, and commodity elevators; mills j and
other facilities. ..
. B States hazardous conditions. under which the Field! Office Supervisors
may .remove Federal employees from the facility, ' . '
I * ' *
C States conditions under which the Field Office Supervisors may refuse
inspection because of prevailing "hazardous conditions."
-H Ts pffprf TV*» i
superseded.
v iinnn Tf>r-firif and T.T-I 1 1 -i-omajri -in
II.
ALERT GUIDELINES STANDARDS AND PROCEDURES
A Reference source and guidelines will be- those 'portions of OSHA General
Industry Standards, 29 CFR 1910; and applicable portions of the National Fire
Prevention Codes., #57 and #61B. These-'WilL be utilized to:_-deterihine whether
facilities or portions of facilities are_considered~"unduly-hazardous" to FGIS~^ '
employees* . . i _
1. FGIS Policy . " . .!-*."
While "unduly hazardous" conditions are unabated,! it shall be -within-the
purview of. -the_7.Eiel:d. Of f ice Supervisor to- order- Federal -employees out-of the «-*
facility :and-to-withho Id inspection, and, weighing; until compliance- or -acceptable
progress~-toward-abatement.,.is.,. attained*- -.
The OSHA Compliarice Office has the responsibility for making the final
determinations of "acceptable progress." . -
DISTRIBUTION: FGIS:IN
36002, 02029, 02269
MANUAL MAINTENANCE INSTRUCTIONS:
. ,.JIew -Instruction, File in Manual,
This Instruction supersedes the
- verbal Instruction issued from
Washington, D.C. on Thursday,
December 29, 1977.
DATE: 1/6/78
-------
:'- J?GIS INSTRUCTION
III. "UNDULY HAZARDOUS CONDITIONS OR PRACTICES" . '",.-' '
' B . The following list includes, but is not limited to, conditions and-
practices which constituted threat to the safety of FGIS employees while
"performing official duties in grain elevators, mills, or similar" facilities:. .
." * 1. ₯hen.--an elevator is ..in operation under the following conditions:.^
,..".. ' a. Relative-humidity-isless-than-/*5%--ani; " . .
. ." t..-the-dust-collection system.is.^inoperable^shut down for,service
''."*. . ."" (Evacuate-- Alert .Field Off ice. Supervisor) '..:""
* 2, The use of portable radios,' (except regulation gover-nment issue)
. ".. . coffee pots, electric heaters, or fans by anyone in. the open, elevator
"'.."<* - , area. (Evacuate - Alert Field Office Supervisor)
* *.'. " " .
-. " . " . ; 3. Welding, torch cutting,' or soldering by anyone. (Evacuate - Alert
'» -" Pield Office Supervisor) :.. "* .- , .- .:
. "." ."' -4. Observation of open flamesj i,e* lighters, matches, burning
".." '. .- cigarettes, pipes, or.cigars by anyone, (Evacuate - Alert Field Office
.' ' * -Supervisor)- .'.*.- "
**' . .
"" ' 5. Observation of sparks from foreign objects, or metal partss or
'" _ __ ..rotating-machinery . mills., .or prinder-Sj or frora nails in shoes.
~:. (Eyiacuate*-J^ert^FJ.eld-.Office Supervisor-)' { « . °
. 6. -"observation of electric sparks generated during operations of
switches, fuses blowing, damages to cables or equipment. (Evacuajta -
. Alert Field Office Supervisor) . . . ' "
**" **
'""* i '
*. 71 -Observation of fire or smoke "in the headhouse or in grain storage
" . " ..bins. (Evacuate - Alert Field Office Supervisor)
8. Observation of slipping"belts on bucket elevators. (Alert Field
. . Office Supervisor) - - ....
* " ."' "* *
* « ' > *
J .'$9- Observation of hot surfaces including light bulbs,- hot bearings, .
" ' slipping V-belts. (Alert Field Office Supervisor - Elevator Management
* : , » , *
.- 10. Observation of static electricity. (Alert Field Office Supervisor
.; . Elevator Management) ..-
". " .. ii. Observation of moving parts running through dust accumulations or
\C_grain spills. (Alerf Field Off ice Supervisor - Elevator Management)
^ 12. Use of unapproved portable lamps in storage bins. (Alert Field
^ .". Office Supervisor - Elevator Management)
- " 13. Poor housekeeping, CSee HFPA-.61B, Chapter""?) (Alert Field Office
.,_ Supervisor) ,
..-' J.4.* Excessive fumigant odors. (Evacuate - Alert Field Office Supervise!
. . « " . '"'*'
'. -. . - -II-2- ' _ . ' . ."»' ...
-------
.,,"-. . * ' - "' .'"'' ' : ' FGIS INSTRUCTION
...v '. "- ''""'*. .-''" -'. .'
'15. Observation of compressed air being used to remove dust from walls
* and ledges, while elevator .is 6perat.ing.- (Evacuate ~ yYlert Field
..' '.' . .Office Supervisor) ^ ' ; . -
» ** *' * ° * * ' ' "
i . . - - 16.'The driving wheels of the engine used for positioning railcars are
v permitted to spinvcausing sparks while on .unloading pit, (Evacuate -
'Alert Field Office Supervisor) "'"*' "".' '';'" '".' "'"" :--"""'
» . ' *"*".*.* - * * ~ . - « .
-*'' " .* * *"*'". "
IV " .RESPONSIBILITIES "*'' . / '";''' . ' -': "-.
: . '"''-A The Safety Office, Standardization Division, is responsible -for plan-
niag and formulating the major safety and health policies and procedures of the
Agency to provide a viable safety program, The" Safety Office is also responsiblf
for accident prevention and control,.safety education and'accident investigation
and analysis to determine the FGIS operations are conducted in compliance with
.applicable OSHA 29 CFR Standardss National Fire Prevention Standards (NFPA) #61B
and 57, and FGIS safety regulations.. ' . .
Xfae address of the-Safety Office is: --'.'.."'' '.---.
^ "" Safety Office, Standardization Division .' !. ''...'-'"
--. . - Federal Grain Inspection Service ' *
D.S. Department of Agriculture ; "
; 1400 Independence Avenue, - SW / . L .'''
Washington, D.,C. 20250 * " ' «:| , '
-'. ' " -Telenhone: (202) 447-9331 " " M . ' . ~
. * £ j '*|** *
B Supervisors shall: . " . ' "
1. ".Be on the alert for hazardous conditions.
' 2. .Exercise judgment in actions with" safety of FGIS "employees being
"a consideration, . *
. 3. Ifamediately contact Elevator Management on actions initiated under
-.Item 'III.
-; 4. Contact OSHA Field Offiee. ..!-.,
- ' .5.. Vigorously enforce all FGIS departmental safety regulations.
' '_ 6. In questionable situations, time permitting, contact the FGIS
.. ' Safety Office or the Employee Relations, and Services Branch, Personnel
. Division, Agricultural Marketing Service, for assistance or concurrence
C Employees shall: I '
, " I**** *
" . **
* * *
le> Observe all safety regulations and procedures.
2. .Be on the alert for their personal safety.
. : ' i
3, Use personal protective equipment as "prescribed.
\ 4» Participate in all emergency evacuation drills and safety programs"
initiated by Elevator Management. *
.11-3 .! .. ' ' -
-------
1
PGIS INSTRUCTION
. ' ' '« '.
.A" Promptly report all hazardous conditions, or unsafe practices '
to-Field Office Supervisor. ' e
** ' <
-5" Comply with the safety and conduct requirements as set forth '
'in this instruction. . . . *-..-
Administrator
II-4 .
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APPENDIX III
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VOLUME FIVE 1975
W75& - I
III-l
-------
III-2
-------
Standard for the
Prevsntion of Fire and Dust Explosions In
Grain Elevators and Bulk Grain Handling Facilities
NFPA No. 6.1B 1973
1973 Edition of No. 61B
This standard was prepared by the Sectional Committee on Grain
aJFoodProcessing 6uSs and was approved by the Dust Explosion
Hoards Correlating Committee. This edition was adopted at the
1973 NFPA Annual Meeting and supersedes the 1970 edition.
The 1970 edition of this standard was approved by the American
National Standards Institute under date of January 27, 1971 .and
Sited ANSI Z12.4-1971. The 1973 edition is being submitted
FoSar approval. The ANSI designation and date of approval
will be" printed on the front_ cover of copies of this edition printed
after approval has been received.
'
Origin and Development of No. 61B ;
No. 6-1B was adopted as a tentative standard in 1969 replacing
lhree former standards: No. 61B, No. 64 and No. 661. Th tenta-
Uve standard, with amendments, was adopted as an offiaal stan-
dard at the 1970 Annual Meeting. j
.
Correlating Committee
T. T. Singer, Cfcrirmon, '
tourance Services Office - Midwestern Region, 230 W. Monroe St., Chi«Zo, II 60«06
W L. Sandsfi Stcritariit
taurance Services Office - Midwestern Region. 230 W. Monroe St., Chicago, IL 80503
Jr American Society of G. D. Perkins, Mill Mutual Fire Prevention
K-iUc^caieE*gia6erJ **" Bureau
uho Noey, U.S. Bureau of Mines and Ja"lfs f
^NFPA !:otumittea on Explosion Protec- Mfa. A
III-3
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CONTENTS 61B-3
CONTENTS
Page
Foreword 61B-5
Scope 61B-6
Chapter 1. Structural Features 61B-7
101. General 61B-7
102. Interior Surfaces 61B-7
103. Walla fiiB-7
104. Bins and Tanks 61B-7
105. Stairs and Elevators 6IB8
106. Marine Towers 61B-8
Chapter 2. Ventilation, Venting and Aeration 61B-9
201. General 61B-9
202. Venting of Bins and Tanks 61B-9
Chaptcr3. Explosion Relief 61B-10
301. General 61B-10
302. Equipment '. . . . 61B-10
Chapter 4. Equipment 6IB11
401. Elevator Legs 61B-11
402. Drives 618-11
403. Processing Machinery 61B-11
404. Clutches and Drive Belts 61B-12
405. Screw Conveyors 61B-12
406. Bearings 61B-12
407. Spouts and Throw of Grain ' . . . 61B-12
Chapter 5. Grain Driers 61B-13
501. Construction of Driers 61B-13
502. Electrical . . 61B-14
503. Location of Driers 6IB-14
504. Fuel Supplies 61B-14
SOS. Heat Producing Devices . . . 61B-14
506. Control Equipment 61B-15
507. Operation of Drier 61B-16
508. Fire Extinguishing Equipment 61B-17
III-4
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GRAIN ELEVATORS AND BULK HANDLING
61B-4
Chapter 6. Dust Control j . . . . 61B-18
601. Dust Collection , 61B-18
602. Dust Collecting System 61B-18
Chapter 7. Housekeeping 61B-19
701. Good Housekeeping 61B-19
702. Removal of Static Dust | . ... . 61B-19
Chapters. Electrical \ 61B-19
801. Wiring and Equipment 61B-19
Chapter 9. Fire Protection 61B-19
901. Fire Protection 61B-19
I
Chapter 10. Miscellaneous 61B-20
1001. Heating 61B-20
1002. Protection Against Sparks | 61B-20
1003. Fumigation 61B-20
1004. Smoking .- 61B-20
1005. Waste Cans |. . . . . 61B-20
1006. Oils ' 1 61B-20
1007. Miscellaneous Storage 61B-20
1008. Lightning Protection . . -! 61B-21
1009. Static Electricity 61B-21
1010. Welding and Cutting 61B-21
1011. Powder-Operated j 61B-22
1012. Outside Grain Storage . . 61B-22
1013. Shovels 61B-22
1014. Grain Temperature Indicators j ...... 61B-22
1015. Internal Combustion Engines [ 61B-22
Appendix - 61B-23
III-5
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FOREWORD, SCOPS
61B-5
Standard for
Grain Elevators and Bulk Grain Handling Facilities
NFPA No. 61 B 1973
Notice: An asterisk^) preceding the number or letter designating.a paragraph
indicates explanatory material on that paragraph in Appendix.
FOREWORD
This standard has been developed to replace _ three existing
MFPA, Podes NFPA. No. 61B, Code for the Prevention of Dust tLx-
fo^cns fclSJS Grain Floors, NF^A No. 64,Co* for to Pre-
oaition of Dust Ignitions in Country Cram Elevators, and NFPA No. 661,
Section and Voting in Grain Elevators. The purpose in consolidating
the three codes-retaining the important features of eacn, was to
provide a single complete standard covering the full range of
recommendations for good design, operating practices and_ pro-
tective features. It should be noted that trends within the industry,
toward utilization of various types of bulk gram storage facilities
surest that a distinction between types of gram elevators on the
basis of capacity or shipping and receiving media is no longer
practical.
These guidelines have been set forth representing current think-
ing on minimizing fire and dust explosion hazards in properties
to which they apply as defined m the scope.
The Standard JOT Dthydrators and Dryers for Agricultural Products
(NFPA No 93) was formally withdrawn in May 1968. For this
reason, Chapter 5, Grain Driers has been included.
SCOPE
This standard has two principal objectives: First, to prevent fire
and dust explosions, and second, to minimize the resulting damage
should a fire or explosion occur.
This standard shall apply to all facilities designed principally
for receiving, shipping, handling or storing agricultural commodities
such as (but not limited to) barley, corn, cottonseed, ftaxseed, milo,
oats, wheat, rice, safflower seed, soybeans, and similar commodities
which may present a fire or dust explosion hazard. .'....
III-6
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61B-6 GRAIN ELEVATORS AND BULK HANDLING
Such facilities include grain elevators, transfer facilities with or
without storage, bulk storage buildings, etc., including grain stor-
age and handling facilities associated with processing plants. For
standards applying to facilities involving further processing of agri-
cultural commodities such as cereal mills, flour mills, or feed mills,
see NFPA Standards 61A, 61C, 61D. 'i
This standard shall apply to facilities erected subsequent to the
date of this standard, and is presented as an advisoiy guide for
owners or operators who may wish to avail themselves of the infor-
mation herein contained in major replacement or renovation of
existing facilities.
III-7
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STRTJCTUBAL FEATURES ' 61B-7
CHAPTER i. STRUCTURAL FEATURES
*101. General
1011. Materials of construction shall be either noncombustible
or fire resistive.
1012. Exterior walls, roofs, roof houses and galleries shall be
designed in conformity with applicable local, state or national
building codes.
*102. Interior Surfaces
*1021. Horizontal surfaces, particularly those that are inac-
cessible or difficult to clean, should be kept to a minimum to reduce
the accumulation of static dust.
103. Walls
1031. Interior walls erected as fire walls, between mills, work
houses, bins, driers, warehouses, track sheds, etc., shall be designed
for a minimum of three hours fire resistance.
1032. Any opening in a fire wall shall be protected by approved
installation of an automatic closing Class A fire door.
1033. Interior walls, erected to segregate dust-explosion hazards,
shall be designed for explosion resistance that will permit proper
relieving of venting areas to the outside without destruction of
these walls.
1034. The use of plastic panels shall be limited to plastics
having a fire hazard classification not exceeding a flame spread
rating of 25 according to method of test of surface burning charac-
teristics of building materials NFPA No. 255, UL No. 723, ASTM
No. E84.
104. Bins and Tanks
1041. Bins and tanks shall be noncombustible or fire-resistive.
1042. Bins and tanks shall be provided with dust-tight and
watertight covers or decks.
1043. There shall be no openings between bins, or tanks.
III-8
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61B-8 GRAIN ELEVATORS AND BULK HANDLING
1044. Where a bin or tank has a manhole provided in the
deck or cover the smallest dimension of the opening shall be at
least 24 inches and the manhole cover shall not emit dust.
*105. Stairs and Elevators
..
1051. Interior stairs and elevators shall be enclosed by fire-
resistive or noncombustible shafts having a fire-resistive rating of
at least one hour.
1052. Stair and elevator shafts shall be protected by approved
installations of automatic closing Class B fire doors on all interior
openings. |
*106. Marine Towers
1061. Marine Towers shall be constructed of noncombustible
materials. j
1062. Movable marine towers shall be provided with adequate
automatic and manual power operated brakes.
1063. Movable marine towers shall be provided with automatic
and manual rail clamps. Provision shall be made for providing
emergency tie-down with guy cables in areas subject to hurricanes.
III-9
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VENTILATION, VENTING AND AERATION
61B-S
CHAPTER 2. VENTILATION, VENTING AND AERATION
201. General
2011. Other chapters of this standard provide specifically for
inclusion of necessary explosion relief designs and dust control.
Ventilation as referred to in this chapter refers to natural heat and
light venting and other air movement as may be necessary for nor-
mal industry operations and for personnel comfort and safety.
Where local,' state or federal regulations govern quantity or type of
paniculate emission to the atmosphere, the following provisions
may be modified to conform with such requirements. However,
any fire or explosion hazards introduced or increased by the modi-
fications shall be provided with the protective features required
by this standard.
*202. Venting of Bins and Tanks
2021. There shall be no direct structural openings between bins
and tanks.
*2022. Each bin or tank, including interstices, shall be provided
with means for adequate air displacement during filling or emptying.
The vent shall be large enough to handle the air displaced by grain
according to the fastest rate of input or removal possible with the
equipment provided (24- cubic feet per minute for each 1,000 bushels
per hour of grain handled not including entrained air).
2023. Where there is a story above the bins, such vent may ne-
cessarily be located in the side of bin immediately below its top,
in which case the terminal of vent shall be of special design which
will not permit wind to blow into vent. No portion of vent shall
be other than vertical if such arrangement is practicable, to prevent
choking with accumulation of dust.
2024. If a vertical stack or air aspiration cannot be installed on
a bin or tank because of interference with operation of house or
because of structural conditions, the stack may be inclined not
more than 30 degrees from vertical and where necessary, two or
more such stacks may be connected to a common header stack and
thence to the outside. Such stacks (including header) may be in-
clined not more than 30 degrees from vertical. There shall be
no intercommunication of bins except through stacks which may
necessarily join in a common header stack as above. Clean-out
doors shall be provided at regular intervals in all nonvertical shafts.
111-10
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61B-10 CHAIN ELEVATOHS AND BULK HANDLING
CHAPTER 3. EXPLOSION RELIEF
301. General
*3011. Explosion relief as used in this standard is intended to
encompass the design and installation of protective features, which
by rSS Ae pressures resulting from a combustion explosion
Scirrfng ?t atmospheric pressures, will minimize damage to the
building or equipment and injury to personnel.
3012 When a dust-explosion hazard exists in ' any building or
struck, sSch building or structure .shall beP-^-.th ex-
plosion relief. For more complete information reier to MfrFA
Standard No. 91, Guide for Explosion Venting.
3013. Explosion relieving panels, windows, or other closures
shall be designed to prevent automatic closure | after relieving a
pressure wave, otherwise an implosion can occur.
*302. Equipment
3021. Elevator legs shall be equipped with ipaxmmm possible
explosion relief through the roof. j
3022 Dust collectors shall be located outdoors or in separate
buildings with the recommended explosion relie for collector and
balding. Where it is necessary to use filter collectors these shaU
be enclosed in a metal housing which m turn shall be P**
with explosion relief. Explosion rehef for equipment shall be de-
2g?edlbrTe minimum of 1 square foot of relief for each 30 cubic
feet of volume.
3023 Dust collection system ducts shall be provided with ex-
plosion relief in accord with NFPA Standard No. 91, Blower and
Exhaust Systems.
3024 Explosion relief for pneumatic conveyor systems shall' be
provided and designed in accord with NFPA Standard No 66
Pneumatic Copying Systems in Handling F
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EQUIPMENT
61B-11
CHAPTER 4. EQUIPMENT
400. General
*401. Elevator Legs
4011. Leg casings, head and boot sections and connecting spouts
shall be dust tight and constructed of noncombustible material.
Plastics used as lining material for such equipment shall be limited
to materials having a'fire hazard classification not to exceed a flame
spread rating of 25 according to method of test of surface burning
characteristics of building materials NFPA No. 255, UL No. 723,
ASTM No. E84.
4012 Inspection door(s) shall be located in the head section to
allow full inspection of head pulley lagging and the pulley side of
the leg belt, preferably on the down leg side.
4013. Leg throat shall be'hoppered to the down leg at an angle
of not less than 45 degrees.
4014 Legs shall be driven by individual motors and drives which
shall be large enough to handle the full rated elevating capacity
without being subjected to overload, but which shall not be larger
than the smallest standard motor rating meeting the above re-
quirements.
4015. If pits are necessary, ample room shall be provided for
cleaning, lubricating and repairing boot.
402. Drives
4021 All elevator legs, conveyors, processing machinery, car-
pullers, winches, drier systems, etc., shall have individual connec-
tions to power source, and shall not be run idle.
*403. Processing Machinery
*4031. Processing machinery shall include equipment for screen-
ing, cleaning, scalping, clipping, scouring, desmutting, grinding,
pulverizing, cracking, shelling, etc., but not for drying.
*4032. Tributary spouts or conveyors feeding grain processing
machinery shall be equipped with a properly installed permanent
or electric magnet, pneumatic separator, screen, or specific gravity-
111-12.
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61B-12 GRAIN ELEVATORS AND BULK HANDLING
I ' '
type :separator to exclude from the processing machinery all metal
or foreign matter of a size larger than the grain being processed.
- i
*404. Clutches and Drive Belts
4041. If friction clutches are used, they shall t>e constructed
entirely of noncombustible material. i
-
4042. Where a belt-type drive is used, the drive shall be de-
signed to add a sufficient service factor to stall the i driving forces
without slipping. : -
405. Screw Conveyors '.
4051. Screw conveyors shall be fully enclosed in nnetal housings,
with free-lifting covers at discharge end and over each shaft coupling.
406. Bearings |
4061. Roller or ball antifriction bearings shall be used on all
machinery, conveyors and processing equipment.
4062. Lubrication inlets on all bearings shall be (provided with
dust caps or other tight closures.
*407. Spouts and Throw of Grain
4071. Fixed spouts shall be dust tight. j
4072.. Portable, automatic distributing, and movable spouts are
permitted in working floor, bin floor or distributing floor areas.
Such spouts shall be made dust tight when in use.
4073. Open top grain chutes and open screens which permit
free escape of dust shall not be used.
111-13
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GRAIN DRIERS 61B-13
CHAPTER 5. GRAIN DRIERS
501. Construction of Driers
5011. General. Driers and the related equipment shall be built
with regard to the hazard inherent in the equipment operating at
elevated temperatures, the hazard occasioned by overheating the
product, open flames, incomplete combustion of direct-fired de-
vices, hazard to operator from mechanical equipment and high
temperatures, and the need of assuring reliable, safe operation over
the expected. life of the equipment.
(a) Driers shall be constructed of noneombustible material.
(b) Expansion joints shall be provided, if necessary, to pre-
vent damage from expansion or contraction.
(c) Driers designed for outdoor use shall be so constructed
or anchored that they can safely withstand wind pressures or snow
loads to which they may be subjected. As a minimum, driers less
than 50 feet in height shall be designed to withstand wind pressures
of 20 pounds per square foot. If over 50 feet, but less than 100 feet
in height, this loading shall be increased to 25 pounds per square
foot, and if over 100 feet, 30 pounds per square foot loading shall
be used. These requirements may be modified to conform to local
building codes.
(d) The primary intake air of the burners shall be screened.
(e) All driers designed to re-circulate a portion of the exhaust
air shall employ a means of removing combustible material from the
air in the re-circulation duct.
(f) In a direct-fired drier using oil or solid fuels, a target plate
or other effective means shall be used to prevent burning materials
from entering the drying chamber.
(g) Interior surfaces of all driers shall be designed to facilitate
cleaning.
(h) Access doors or openings shall be provided to permit in-
spection, cleaning and maintenance, and also the. effective use of
extinguishers or hose streams in all parrs of the drier and the con-
necting spouts or conveyors. All access doors which permit per-
sonnel entry shall be provided with hardware which will permit
manual opening without tools from either side of the access door.
(i) Intake and discharge hoppers for driers shall be so designed
that they will be accessible to permit cleaning in the event of
stoppage.
111-14
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61B-14 GRAIN ELEVATORS AND BULK HANDLING _ __
(j) Means shall be provided to rapidly unload (dump) -the
drier in case of fire.
502. Electrical .'.'.- L .
5021. Electric motors shall-be installed so that ventilation is
provided. [
*503, Location of Driers
~~ 5031 Drying processes conducted in buildings likely- 4:o contain
combustible dust shall have heating devices and blowers located
in a separate dust-tight room or area. Such rooms or areas shall not
communicate with portions of a building subject to dust. Surfaces
of structural members and all other objects in this'area shall be
designed to reduce to a minimum any accumulation of dust.
5032. Exhaust air-from driers shall be directed tp the outside.
I
504. Fuel Supplies . \ .. . _.
5041. Fuel supplies_up to die point of connection with the drier,
where applicable, shall comply with the following Standards: NFPA
No 30 Flammable Liquids Code; NFPA. No. 31, Standards for the Installa-
tion of Oil Burning Equipment; NFPA No. 54, Standard for the Installa-
tion of Gas Appliances and Gas Piping; NFPA No. 55, Storage and
Handling of Liquefied Petroleum Gases; NFPA No. 70,, National Elec-
trical Code.
505. Heat Producing Devices
5051. Combustion controls shall comply with provisions as de-
fined in NFPANo. 86A,'Standard for Ovens and Furnaces.
- 5052. GAS FIRE DEVICES. All gas-fired heat producing devices
shall be of an approved type. Heat producing devices using LP-
Gas and using vaporizer burners shall comply with Construction
and control requirements as specified in NFPA No: 58, Standard
for the Storage xd Handling of Liquefied Petroleum Gases. --
5053..' Gas burners and associated mixing equipment shall be
Suitable for the "service intended -as' follows:. -I - :" .-
(a) For BTU content of gas used. '
(b) For operating pressures furnished. j
(c) Capable of maintaining flame stability throughout turn-
down range.
(d)- Desisted to permit use of .required safety interlock.
111-15
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GRAIN DRIEHS 61B-15
5054. Pilots shall be of an approved type.' Under conditions
where reliability of direct electrical ignition of the main burner(s)
is questionable, flame-type pilot ignition shall be used.
5055. Purge cycle shall accomplish at least four complete changes
of air in all areas of the drier. , .
5056. OIL-FIRED DEVICES. All,types of heating devices that use
liquid fuels shall be of an approved type.'
50561. Design of the combustion chamber shall be such that
combustion of the air-oil mixture will be completed within the
chamber throughout the turn-down range of the control equipment.
50562. Pilots shall be of an approved type. Under conditions
where reliability of direct electrical ignition of the main burner(s)
ia questionable, flame-type pilot ignition shall be used.
50563. Oil shall not be delivered to the burner by gravity.
5057. HEAT TRANSFER DRIERS. All types of heat transfer de-
vices that use heat transfer media such as steam, air or vapors of
other media, some of which are combustible, shall comply with
the following requirements:
(a) Relief valves shall be provided where necessary and re-
lief valves on systems employing combustible liquids shall be vented
to the outside.
(b) Enclosures for heat exchangers shall be of noncombustible
construction with access openings for maintenance and cleaning.
(c) Heat exchangers shall not be located or arranged in such
a manner that combustible dusts are likely".to accumulate on the
coils, fins or other heated surfaces.
506. Control Equipment
5061. Control equipment shall be of such construction and de-
sign and so arranged that required cgndltibps of safety for the op-
eration of the heat-producing device,'the drier, and the ventilation
equipment used, will .be maintained. In addition to combustion
and ignition controls there shall be provided automatic means for
shutting down the drier and its auxiliary'equipment in the event
of a fire or the development of excessive heat within the drier.
5062. All control equipment shall be nonrecycling or shall ac-
complish a nonrecycling shutdown and require a manual reset be-
fore the drier can be again placed in operation following a safety
control shutdown.
111-16
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61B-16 GRAIN ELEVATORS AND BULK HANDLING
5063. A maximum temperature thermostat shall be located be
Uveen the heat-producing device and the drier.
5064. Driers shall have a thermostat to control induced air
temperature mside drying compartment.
fm506,!' ?r-iCrS fr°m Whkh the dried Produ« moves automatically
from the drier to the storage building shall have a maximum tern-
* ltCh 1
-
, in ^ exhaust air stream- Driers in
the dried product moves manually should have'one or more
.maximum temperature limit switches located in the exhaust a?r
stream. The operation of these controls shall :
(b) InteiTUpt the flow of the Pr°<^ct into and away from' the
(c) Sound- an audible alarm.
wiU°rm nV,°n f1 f'T" °f Suitf.bie desi&n sh*U be provided which
will cut off all heat being supplied to the drier should the move-
atr flow r ^OUSh
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GRAIN DRIERS 61B-I7
5075 Manufacturers shall furnish operating instructions which.
will specifically indicate safe operating and processing limitations
for each drier.
5076. Operating personnel shall be fully instructed in the safe
operation of the drier.
5077. Drier shall be monitored while In operation.
*508. Fire Extinguishing Equipment
111-18
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61B-18 GRAIN ELEVATORS AND BULK HANDLING
CHAPTER 6. DUST CONTROL
601, Dust Collection
6011. Dust shall be collected at all dust producing points within
the processing facilities.
6012. All elevator boots shall be provided-with air ^aspiration.
6013. Automatic scales -shall be provided with enclosures or
dust hoods and air aspiration.- : _ _
6014. Scale hoppers shall be enclosed at the top and air aspira-
tion provided at both the top and discharge. " ;
^ i '
6015. All belt loaders shall be provided with air aspiration.
6016. Air aspiration shall be provided on all belt discharges,
trippers, distributor heads, and at the end of all belts.
6017. All machinery such as cleaners, scalpers and similar-de-
vices not designed to be dust tight shall be provided with air aspira-
tion. -;..-'- I -
i
602. Dust Collecting System
6021. The entire dusrcollecting system shall conform to NFPA 1
No. 91, Standard Jor the Installation of 'Blower and- Exhaust Systems. !
-6022. All component parts of the dust collection system located
inside the elevator structure shall be :of "noncombustible~rhaterial.
"6023. Dust collectors shall be located outside of buildings or in
a noncombustible room outside the grain storage and'Handling
structure. Such building or room shall comply with all provisions
set forth in NFPA No. 66, Standard for Penumatic Conveying Systems JOT
Handling Feed, Flour, Grain and other Agricultural Dusts. \
6024. The dust liberated by car or truck unloading,.!and espe-
cially where car dumpers are used shall be controlled by enclosing
as much of the top of the track hoppers as possible by "applying
positive air aspiration to such enclosures. j
6025. Dust bins shall be of noncombustible construction, de-
tached-from other buildings, equipped with a normally closed
fire stop in connecting ducts and provided with suitable fire de-
tection and extinguishing devices.
II1-19
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HOUSEKEEPING, ELECTRICAL, FIRE PROTECTION 61B19
CHAPTER 7. HOUSEKEEPING
701. Good Housekeeping
7011. Good housekeeping and dean premises are the first es-
sentials for elimination of dust explosion hazards, consequendy
this standard is not intended to lessen in any way the responsibility
of the owner or operator in this respect. It should also be em-
phasized that any potential fire cause may produce a dust explosion.
*702. Removal of Static Dust
*7021. Dust on floors, ledges, girders, machinery, spouting and
other surfaces, including all galleries and tunnels shall be removed
concurrendy with operations, to prevent accumulation of such dust.
7022. Spills, and chpkes shall be cleaned up without delay.
7023. The use of compressed air or other means to blow dust
from ledges, walls, and otiier areas which will create a dust explosion
hazard shall not be permitted unless all machinery in die area has
been shut down and all sources of ignition removed.
CHAPTER 8. ELECTRICAL
801. Wiping and Equipment
8.011. Electrical equipment shall conform with the provisions of
Articles 500 and 502 of NFPA No. 70, National Electrical Code or the
Canadian Electrical Code, as applicable.
CHAPTER 9. FIRE PROTECTION
*901. Fire Protection
9011. PORTABLE FISE EXTINGUISHERS. Portable fire extinguishers
shall be provided throughout all buildings in accordance witii
NFPA No. 10, Installation of Portable Fire ' Extinguishers, with par-
ticular reference to requirements for the protection of Class C
(electrical) hazards.
Ill-20
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61B-20 GRAIN ELEVATORS AND BULK HANDLING
i
CHAPTER 10. MISCELLANEOUS
1001. Heating
10011. Heating shall be steam or hot water from a boiler in an
approved location, or from electric hot water radiators of a type
approved for Class II locations. Steam pipes exposed to dust ac-
cumulations shall be protected by suitable insulation having con-
tinuous nonporous covering or skin of adequate thickness to keep
the surface temperature below 160° F. |
- i
1002. Protection Against Sparks
10021. All openings less than 50 feet above ground, in exterior
walls on track or dock side, shall be protected against sparks, by
screens.
-
*1003. Fumigation
10031. Processes and chemicals for fumigation shall be in ac-
cordance with the requirements of NFPA No,; 57, Standard for
Fumigation.
1004. Smoking
10041. Smoking shall be prohibited except in i designated areas.
1005. Waste Cans
10051. Approved containers shall be provided, all oily waste
and other rubbish deposited therein, and emptied daily.
1006. Oils
10061. Main storage of lubricating oil, grease and other flam-
mable liquids shall be in a detached location. Storage of lubri-
cating oil and grease in the elevator shall be limited to a maximum
of five barrels and shall be in a separate room of noncombustible
construction.
*1007. Miscellaneous Storage
10071. Storage of ammonium nitrate shall be iri accordance with
the provisions of NFPA No. 490, Storage of Ammonium Nitrate.
111-21
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MISCELLANEOUS
61B-21
1008. Lightning Protection
10081. Lightning protection, if provided, shall be installed in
accordance with NFPA No. 78, Lightning Protection Code.
1009. Static Electricity
10091. Static electricity shall be removed from such machines
or equipment as accumulate a charge, by permanent ground wires,
and from belts by grounded metal combs or other effective means.
Grounds shall be in accordance with the provisions of NFPA
No. 77, Recommended Practice on Static Electricity.
1010. Welding and Cutting
10101. Welding and cutting operations are potentially one of the
most hazardous operations that may be conducted in grain storage
and handling buildings. This is particularly true because of the
combustible dust and other refuse which might be found in the
immediate vicinity where welding or cutting is carried out (see
NFPA No. 5 IB, Standard for Fire Protection in Use of Cutting and
Welding Processes).
10102. Written permission shall be given by the manager _ or
superintendent, or other recognized officer, before each welding
or cutting job is undertaken.
10103. All machinery'and dust producing operations from which
dust may reach the area or within range of welding sparks shall be
shut down prior to the start of the welding or cutting job and
remain inoperative until the job has been' completed and final
inspection is made.
10104. Sweep clean and wet down floors, and surroundings, in-
cluding the floor immediately below before welding and cutting job
is commenced. ' .
10105. All floors or wall, openings within 35 feet shall be tightly
sealed to prevent passage of sparks and all combustible material
which cannot be removed from the area shall be protected by
suitable flameproof covers or guards.
10106. If a major welding or cutting job is to be undertaken,
and the plant cannot be shut down, special requirements will be
outlined as required in paragraph 10102.
10107. INSPECTION ON COMPLETION OF JOB. Flying sparks from
welding are frequently thrown or fall into places where the ma-
terial smolders for hours before bursting into flame. A careful in-
spection of all areas near the welding scene, including the floors
111-22
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61B-22 GRAIN ELEVATORS AND BULK HANDLING ;
above and below, shall be made when the job is finished, and such
areas shall be patrolled for a period long enough to make certain
that no smoldering fires have developed. '_
1011. Powder-Operated Tools , - .
. 10111. Gun-type tools using powder or cartridges for (driving
pegs or pins into concrete, brick, steel, etc., shall not be used where
combustible dust or dust clouds are present. When the use of this
type of equipment becomes necessary, all dust producing machinery
in the area shall be shut down, all equipment, floors and walls shall
be carefully cleaned, and all dust accumulations removed. -A-
careful check shall be made to be sure that no cartridges or charges
are left on the premises where they could enter equipment or be
accidentally discharged after operation of the dust producing or
handling machinery is resumed.
i
*1012. Outside Grain Storage
*1013. Shovels
*1014. Grain Temperature Indicators
*1015. Internal Combustion Engines
111-23
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Al'PENDIX 61B-23
APPENDIX
This Appendix is not a part of this WFPA Standard . . . but is in-
eluded for information purposes only.
A101. General: Grain storage and handling facilities should be
maintained as separate fire areas from mills or other major process-
ing installations.
A102. Interior Surfaces: Surfaces, both horizontal and vertical,
should be smooth to facilitate cleaning. .
A1021. Horizontal Surfaces: Inaccessible for adequate cleaning,
should be inclined as steeply as possible.
A105. Stairs and Elevators: Manlifts should be enclosed and pro-*
tected as required in 1051 and 1052. '
AlOfi. Marine Towers: Marine towers should be cut off or de-
tached sufficiently from the elevator to preclude major damage to
the elevator from an explosion occurring in the tower.
Movable marine towers should be provided with suitable equip-
ment to sense wind velocities and automatically set brakes and rail
clamps when wind velocities exceed 35 miles per hour.
A202. Venting of Bins and Tanks: All vents, wherever practicable,
should be vertical stacks, and should be equipped with a weather
hood of a type that will not permit wind to blow into the vent.
A2022, Aeration: The use of permanently or temporarily installed
fans to draw or force unheated air through a silo or tank of grain
which is at an elevated temperature, should include the following
principles:
Temperature indication devices should be installed in bins and
interstices for surveillance of grain temperatures.
When two or more bins are manifolded into a common duct for
the entrance or exit of air, blast gates or equivalent shutoffs should
be provided on each individual bin duct.
111-24
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61B-24 GRAIN ELEVATORS AM> BT7LK HANDIJNG
a nr f Pi u PrfSUre fan SyStem ^ "sed to force air into
a silo or tank with subsequent free air existing, at the top suf-
ficient venting to the outside should be provided Where sufficient
eentln Provided> an aspirating fan to the oSde
dust-Iaden
A3011. Buildings and Structures: All exterior walls and roofs
above or below the bins or tanks in the workhouse ard st<«£e
anH^ TH °f ?C deVat0r' ^ Ae waUs of *<
thtr, H S ai?d -^ ru°°6 °f ^ buHdklgs or ««tio
where a dust explosaon hazard may exist should be
S
waUs of es
°f ^ buHdklgs or ««tion» of bdin J
? sr
areas'wa11 «?Ptota» Belief must provide^ To"
aodd,v , ', «?P» Be
avoid development of excessive pressures.
unr«tricted areas should be provided with stops in the
?Te°^ UStlbIC Pardti0nS with -^dorinff doors /Wt Se
t the name-propagation wave.
All buildings should, insofar as is possible, be constructed suf
aVegr'*d1'!VClSO th" "a '"'"k
and should be ac-
<*
n *=u,d b. so
nr-25
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APPENDIX 61B-25
All elevator legs should be provided with an automatic me-
chanical or electromechanical device to shut off all driving power
and sound an alarm in the event of belt slowdown or a separation
of the leg belt. Tributary conveyors (all types) which feed the ele-
vator leg should be equipped with an interlocking device to auto-
matically shut off power simultaneously when power to the ele-
vator leg is interrupted.
A403. Processing Machinery: All processing machinery should
be of noncombustible materials.
A4031. All grain processing machinery should be mounted at
least 8 inches above the floor to allow access for cleanup, unless
such machinery is constructed with a tight base preventing grain
from reaching inaccessible places beneath the machine.
A4032. Tramp Metal Removal: Grain and dry ingredient re-
ceiving facilities should be equipped with permanent magnets, ap-
proved electromagnets or specific gravity-type separators to pre-
vent the entry'of tramp metal into grain handling or processing
machinery. Such devices should be installed on conveyors or spout-
ing handling grain from truck dump hoppers, rail car hoppers
barge unloading and ship unloading systems prior to the entry of
the grain into subsequent conveying, elevatine, or processing ma-
chinery.
A404. Clutches and Drive Belts: When drive assemblies must
necessarily involve the use of belts (V-belts or flat belts), such belts
should be of approved static-conduction type.
A407. Spouts and Throw of Grain: Throwing of grain in the
open for considerable distances (not confined to spouts)' should not
be permitted, except where absolutely necessary in, open or semi-
confined spaces as in the case of barge loading, ship loading, or rail
car loading or in large bulk grain storage areas.
Spouts introducing grain into tanks, bins or garners, should be
designed and installed in such a manner that the grain stream will
not strike the wall of the bin, to avoid the possibility of generating
sparks with entrained tramp iron.
Space Under Conveyors: At least 8 inches of clear space should
be provided; between return, rollers supporting conveyor, belts arid
the floor, to provide sufficient: access for cleaning.
Nonchoking of Elevator tegs: All spouts, garners, bins,, etc.
should be designed to handle the} full, rated cap.actiy of the largest
111-26
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61B-26 GRAIN ELEVATORS AND BULK HANDLING j '
!~~ "
elevator leg feeding them.-;_Such receptacles should have automatic
overflow systems or be equipped with approved high-level visual or
audible indicating devices. .....'"
I
I- *'
A5030 Location of Driers: Driers and related equipment includ-
ng fuel hnes and fuel storage should be located with due regard to
the possibdity of fire resulting from overheating or from the escape
Slv f °r Sn^C Possibility °f injury to persons or damage to
the containing building. j $ u
Provisions | should be made for safe removal of overheated products
trom the building. , r . "
an and related equipment, including fuel lines
and fuel storage should be located with due regard to the possibiliS
of fire resulting from overheating or from the escape of fuel gas or
oil and the possibility of injury to persons or damage to adjacent
buddings or structures Driers should be separated fronAthw
structures, including other dners, by approved fire walls without
openings, other than openings for spouts or conveyors, or separated
by clear space as follows: - |
Byn5 ^u °f d-ear spaee where exPQsed structures have
provided such openings are protected
Byn10 ^ °f dear space where exPosed structures have
W Unpr°teCted °Penings, or are of noncombustible
. (c) BY 15 feet of clear space where- exposed structures are of
frame, frame ironclad or other types of combustible construction.
|-
A508._. Fire Extinguishing Equipment
in5?5 LMtanat«>n. .Driers should be provided with permanently
mstaJed means of extinguishing fires within drier enclosures. The
nature and extent of the protection required will depend upon the
comtruction and arrangements of .the drier and, its enclosing sUc-
ture, if any, and the product being processed.
fnrl-iS fecommended thaJ on« °f the following means be employed
^ the drying enclosure. Th'y Le
(1) Fixed water spray devices or sprinklers supplied by an ade-
°-c15' WatST S^ F^d **&'
' Standardf°r the illation o
111-27
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APPENDIX .61B-27
(2) One- and one-half-inch hose of sufficient length to reach all
access openings on the drier, supplied by a 2-inch or larger water
pipe, and adequate source. (See NFPA No. 14, Standard for 'the In-"
stallalion of Standpipe and Hose Systems.)
(3) Small diameter hose of sufficient length supplied from do-
mestic source, when more adequate supply is not available.
NOTE: Direct-fired rotary driers which may be damaged internally by
application of water should be provided with ports or other means which
will permit the injection of carbon dioxide or stream.
Portable Fire Appliances. One or more portable extinguishers
approved for use on Class A fires should be provided for use within
or in the vicinity of the drier enclosure, and one or more approved
extinguishers having a rating of 8-B :C or better shall be provided
for electrical fires. (See NFPA No. 10, Standard for the Installation
of Portable Fire Extinguishers.")
A702. Removal of Static Dust. Push brooms of hair or soft fiber
should be used as they will dirow less dust into suspension dian ordi-
nary brooms, and are better adapted to sweeping under belts and
other machinery.
A7021. Vacuum Sweeping Apparatus. Installation of approved
permanent, semipermanent portable * vacuum cleaning systems
should be provided for removal and collection of normal static dust
deposits.
When floor sweeps are provided, air velocity through such floor
sweeps shall be sufficient to pick up and carry such dust deposits
including incidental kernels of whole grain which may be present.
A901. Fire Protection
Automatic Sprinklers. An approved system of automatic sprin-
klers should be provided for the protection of all areas containing
combustible materials (odier than grain). For grain risks located
in areas with inadequate water supplies for a standard system
of automatic sprinklers, 'the"installation"' of sprinklers in elevator
cupolas and other areas containing combustible materials supplied
by a dry standpipe with outside fire department connection should
be provided.
Supervisory Services. For prompt detection of fires, either a
watchman, an automatic fire detection system or sprinkler water
flow and supervisory system "should be provided. If -guard service
is provided, routing, the recording apparatus, etc., should be as
recommended in NFPA No. 601, Recommendations for Guard Services
'111-28
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61B-28 GRAIN ELEVATORS AND BULK HANDLING
in Firs Loss Prevention. Automatic fire detection systems to actuate
local alarm or other suitable arrangement for automatically notify-
ing fire department in event of fife should be provided in accordance
with the provision of NFPA No. 72A, Local Protective Signaling Sys-
tems or NFPA No. 72C, Remote Station Protective Signaling Systems.
Standpipe and Hose. Standpipe systems should be installed
to protect all areas containing combustible materials as provided
in NFPA No. 14, Standpipe and Hose Systems. One- and one-half-inch
hose and combination fog and straight stream nozzles should be used.
Hydrants. Either public or private fire hydrants supplied by
adequate water system should be provided for fire fighting use.
^ Explosion Suppression. Approved explosion protection systems
designed for instantaneous detection and suppression of impending
explosions are available for use in confined areas such as bins tanks!
dust collectors, etc. Use of such devices should be considered m
unusually, hazardous areas where other means of hazard control
are not suitable. Such devices should be in accordance with NFPA
No. 69, Explosion Prevention Systems. \
Fire Fighting Operations. Fire Department or hose streams
should be used with great care in grain elevators and other grain
handling risks, as hose streams carelessly used may disperse static
dust, cause structural damage to bins, or lead to quality deterioration
of gram. i
A1G03. Fumigation. Because of toxicity and possible fire hazard
fumigants should be stored in a detached building used for no other
purpose.
i
i
A1007. Miscellaneous Storage. There should be no storage of
sacks, sacked gram, screenings, combustible merchandise, materials,
unused machinery, parts and supplies within handling and erain
storage buildings. s
i
i
A1012. Outside Grain Storage. Care should be exercised in se-
lection of outside bulk storage areas to avoid exposure from ad-
joining structures.
Tarpaulins used for covering grain should be flame-resistant
treated. Plastic sheeting used for the purpose should be of slow-
burning or self-extinguishing type.
111-29
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APPENDIX
61B-29
A1013. Shovels. Hand shovels used in shoveling of grain, dust and
other refuse on concrete or steel bin bottoms, floors, etc., should be
made of nonsparking materials.
A1014. Grain Temperature Indicators. An approved installation
of grain temperature indicators should be installed in all grain
storage facilities. The number and location of detectors should be
in accordance with manufacturers' specifications. Control and re-
cording equipment shall be installed in accordance with NFPA
No. 70, National Electrical Code.
A1015. Internal Combustion Engines. Grain handling equip-
ment using internal combustion engines, except those labeled for
Class II, Division 1, Hazardous Locations, should not be used inside
any grain handling or storage plant.
II1-30
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-450/2-77-001b
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
STANDARDS SUPPORT AND ENVIRONMENTAL IMPACT
STATEMENT VOLUME 2: FOR GRAIN ELEVATOR INDUSTRY
5. REPORT DATE
April, 1978
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
4..SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
VOLUME 2 SUMMARIZES THE PUBLIC COMMENTS ON THE PROPOSED STANDARDS, EPA RESPONSES
AND A DISCUSSION OF DIFFERENCES BETWEEN THE PROPOSED AND PROMULGATED STANDARDS
16. ABSTRACT ; \
.
STANDARDS OF PERFORMANCE FOR THE CONTROL OF PARTICULATE MATTER EMISSIONS'
FROM NEW, MODIFIED, AND RECONSTRUCTED GRAIN TERMINAL ELEVATORS AND CERTAIN STORAGE
ELEVATORS AT GRAIN PROCESSING PLANTS ARE BEING PROMULGATED UNDER THE AUTHORITY
OF SECTION 111 OF THE CLEAN AIR ACT. GRAIN ELEVATORS ARE A SIGNIFICANT SOURCE
SJo???mI?TbASJ!Ar'ER EMISSIONS- STUDIES INDICATE THAT, AS A GENERAL. CLASS,-
PARTICULATE MATTER CAUSES ADVERSE HEALTH AND WELFARE EFFECTS. THE PROMULGATED
STANDARDS WILL REDUCE UNCONTROLLED PARTICULATE MATTER EMISSIONS BY MORE THAN-
99 PERCENT AND-WILL REDUCE PARTICULATE MATTER EMISSIONS BY 70 to 90 PERCENT
COMPARED TO EMISSION LIMITS CONTAINED IN TYPICAL STATE OR LOCAL AIR POLLUTION
REGULATIONS.- AN ANALYSIS' OF THE SIGNIFICANT CHANGES IN THE ENVIRONMENTAL AND "
ECONOMIC EFFECTS ASSOCIATED WITH THE PROMULGATED STANDARDS IS INCLUDED IN THIS
DOCUMENT. . -
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
AIR POLLUTION
POLLUTION CONTROL
STANDARDS OF PERFORMANCE
GRAIN ELEVATORS
PARTICULATE MATTER
AIR POLLUTION CONTROL
13. DISTRIBUTION STATEMENT
UNLIMITED
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
20. SECURITY CLASS (Thispage)
UNCLASSIFIED i
22. PRICE
EPA Form 2220-1 (9-73)
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