POLLUTION PREVENTION OPPORTUNITY ASSESSMENT
MANUFACTURING AND FABRICATION REPAIR LABORATORY
AT SANDIA NATIONAL LABORATORIES
by
George Wahl and Kurt Whitford
Science Applications International Corporation
Cincinnati, Ohio 45203
EPA Contract No. 68-C8-0062, WA 3-51
SAIC Project No. 01-0832-03-1003-010
Project Officer
; James Bridges
Pollution Prevention Research Branch
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
The information in this document has been funded wholly or in part by the
United States Environmental Protection Agency under Contract 68-C8-0062 to
Science Applications International Corporation. It has been subjected to the
Agency's review, and it has been approved for publication as an EPA document.
Mention of trade names or commercial products does not constitute endorsement or
recommendation for use. !
-------
FOREWORD
Today's rapidly developing and changing technologies and industrial
products and practices frequently carry with them the increased generation of
materials that, if improperly dealt with, can threaten both public health and the
environment. The U.S. Environmental Protection Agency is charged by Congress
with protecting the Nation's land, air and water resources. Under a mandate of
national environmental laws, the agency strives to formulate and implement
actions leading to a compatible balance between human activities and the ability
of natural systems to support and nurture life. These laws direct the EPA to
perform research to define our environmental problems, measure the impacts and
search for solutions.
The Risk Reduction Engineering Laboratory is responsible for planning,
implementing and managing research, development and demonstration programs to
provide an authoritative, defensible engineering basis in support of the
policies, programs and regulations of the EPA with respect to drinking water,
waste water, pesticides, toxic substances, solid and hazardous wastes, and
Superfund-related activities. This publication is one of the products of that
research and provides a vital communication link between the researcher and the
user community. '• •
The Pollution Prevention Research Branch of the Risk Reduction Engineering
Laboratory has instituted the Waste Reduction Evaluations at- Federal Sites
(WRIEAFS) Program to identify, evaluate and demonstrate pollution prevention
opportunities in industrial, military and other Federal facilities. EPA believes
the WREAFS Program will show pollution prevention to be a cost-effective tool in
reducing the generation and disposal of hazardous and non-hazardous wastes. This
report summarizes a pollution prevention opportunity assessment of the
Manufacturing and Fabrication Repair Laboratory (MFRL) at Sandia National
Laboratories in Albuquerque, New Mexico. The MFRL repairs electronic assemblies
including printed circuit boards which are primarily used for satellite
applications.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
-------
ABSTRACT
This report summarizes work conducted at the Manufacturing and Fabrication
Repair Laboratory (MFRL) at Department of Energy's (DOE's) Sandia National
Laboratories (SNL) facility in Albuquerque, New Mexico as part of the U.S.
Environmental Protection Agency's (EPA) Waste Reduction Evaluations at Federal
Sites (WREAFS) Program. This project was funded by EPA and conducted in
cooperation with DOE officials. ;
The purposes of the WREAFS Program are to identify new technologies and
techniques for reducing wastes from industrial processes at federal sites, and
to enhance the implementation of pollution prevention through technology
transfer. New techniques and technologies for reducing waste generation are
identified through pollution prevention opportunity assessments and may be
further evaluated through joint research, development, and demonstration
projects.
A pollution prevention opportunity assessment was performed during July
1992 which identified areas for waste reduction at the MFRL. The study followed
procedures in the EPA Facility Pollution'Prevention Guide (EPA/600/R-92/088) and
the EPA Guides to Pollution Prevention: ! The FabricatedMetal Products Industry
(EPA/625/7-90/006). Although the MFRL has made substantial progress to date,
opportunities were identified for further action. This report presents potential
personnel/procedural initiatives as we!] as recycling/reuse options to achieve
further pollution prevention progress.
The primary wastes considered were those not associated with the vapor
degreaser. The vapor degreaser is the subject of ongoing research by DOE
officials. The four major pollution prevention options identified were:
test/reuse rinse water if found to bejnon-hazardous, eliminating the use of
ziplock bags with the use of a labpack,^ breaking off the contaminated ends of
swabs, and eliminating bench cleaning of printed circuit boards. Research needs
were identified for appropriate options.
This report was submitted in fulfillment of Contract No. 68-08-0061 by
Science Applications International Corporation, under the sponsorship of the U.S.
Environmental Protection Agency. This report covers a period from 1 October 1992
to 30 April 1992, and work was completed as of 30 September 1992.
IV
-------
CONTENTS
;- - Page
Disclaimer ii
Foreword i i i
Abstract i v
Tables i „ V1-
Figures vii
Acknowledgements viii
Introduction ... 1
Process Review . . 4
Assessment 11
Feasibility of Options . 16
Crossfeed to Other DOE Facilities 19
Measurement of Pollution Prevention . . . 20
Implementation Plan .... : 21
Research Development and Demonstration Needs ... .... 22
Recommendations/Conclusions ... 24
References ; 25
Appendix: PPOA Worksheets ... 26
-------
TABLES
Number
1 Summary of Pollution Prevention Options ............. 18
-------
FIGURES
Number ; Page
1 Pollution Prevention Overview 2
2 Electronic Board Repair within MFRL 5
3 Electronic Board Repair outside MFRL . . 6
4 Total Annual Waste Generated at MFRL 7
i
5 Quantities of Other Wastes Generated at MFRL ...... 7
Vll
-------
ACKNOWLEDGEMENTS
The authors wish to acknowledge the help and cooperation provided by Mary
Akins, Irene Dugger, Randy Kreinbrink, David Barnes, Hugh Reilly, and Dorothy
Stermer of Sandia National Laboratories. Other Sandia employees and officials
at the facility were also very helpful and cooperative. In addition, information
provided to us by vendors of equipment and services, was appreciated.
vm
-------
INTRODUCTION
Purpose
Pollution Prevention Opportunity Assessments (PPOAs) at Sandia National
Laboratories (SNL) were designed to fulfill several purposes. The primary
purpose was to identify pollution prevention opportunities within two
laboratories that typify a large percentage of operations at the Albuquerque
facility. By participating in the PPOA process, SNL waste minimization network
personnel (MinNet Representatives) would learn the mechanics of the process and
be able to conduct future PPOAs. Knowledge gained from the PPOAs would be
distributed throughout the U. S. Department of Energy (DOE) to assist other
facilities in their pollution prevention efforts. Also, the findings from the
PPOAs would direct future pollution prevention research and projects]
This report describes a;PPOA for the Manufacturing and Fabrication Repair
Laboratory (MFRL) at SNL, Albuquerque, New Mexico. The assessment was conducted
for the EPA's Risk Reduction Engineering Laboratory under the purview of the
Waste Reduction Evaluations ^at Federal Sites (WREAFS) program of the Pollution
Prevention Research Branch. The WREAFS program, whose purpose is to identify and
promote the use of pollution prevention techniques and technologies through
technology transfer, provided an appropriate vehicle to accomplish these
purposes. Under the WREAFS Program, innovative pollution prevention
opportunities and alternatives are identified, and may then be evaluated through
research, development, and demonstration (RD&D) projects. In the past, EPA has
initiated and conducted both;individual and joint RD&D projects that investigate
pollution prevention alternatives. The results of these projects are provided
to both the public and private sectors through various technology transfer
mechanisms, including: project reports, project summaries, conference
presentations, workshops, and EPA information clearinghouses, libraries and
document repositories such as NTIS.
Procedures described in the EPA Facility Pollution Prevention Guide
(EPA/600/R-92/088) and the EPA Guides to Pollution Prevention: The Fabricated
Metal Products Industry (EPA/625/7-90/006) were used to conduct the study. The
manual provides detailed worksheets and a process/option evaluation method for
use in industrial settings. PPOA worksheets were completed for the process; the
detailed worksheets are presented in Appendix A. This PPOA consisted of two
systematic phases: assessment and feasibility, analysis (see Figure 1). The
implementation of the recommended options presented in this report is at the
discretion of the host facility. ;
-------
Establish Pollution Prevention Program
• Executive Level Decteion
• Policy Statement
« Coneenwj* Building
Organize Program
« riam* T««k Force
• StttaGaata
Do Preliminary Assessment
• Collect D«U
•, Review Site*
• Establish Priorities
Write Program Plan
• Consider External Group*
• Define Objective*
• Identify Potential Obstacle*
« D»V»|OD Schedule
Do Detailed Assessment
• Name Aceeeement Team(*>
• Review Data end Sited)
« Organize and Document Information
Define Pollution Prevention Options
• Propose Option*
» Scraon Option*
Do Feasibility Analyses
» Technical
• Environmental
o Economic
Write Assessment Report
Implement the Plan
• Select Project*
• Obtain Funding
»: Install
Measure Progress
• Acquire Oat*
* Analyze Raaulta
Maintain Pollution Prevention Overview
Figure 1. Pollution Preven; on Program Overview.
-------
Approach '
SNL is owned by the U.S. Government and is operated by Sandia Corporation,
a subsidiary of AT&T, under a prime operating contract with the DOE. SNL is
located south of Albuquerque, NM, within the boundaries of Kirtland Air Force
Base (KAFB), in Bernalillo County. SNL consists of five technical areas and
several remote test areas. jSandia's primary mission is national security, with
principle emphasis on nuclear weapon development and engineering. In the process
of carrying out this mission, Sandia has evolved into a multiprogram laboratory
pursuing broad aspects of national security issues. As byproductsiof production,
research and development, and environmental restoration activities, Sandia
generates a variety of waste materials that are carefully controlled during
operations and regulated by the federal government and state and local agencies
(Sandia National Laboratories, 1991). !
SNL has developed a written waste minimization plan, in compliance with DOE
Order 5400.1. As part of thjis plan, the Waste Minimization Network (MinNet) has
been created to carry out the Waste Minimization and Pollution Prevention
Awareness Program. MinNet representatives assist the line organizations in
planning, organizing, and ,directing those activities related to pollution
prevention (e.g., conducting Process Waste Assessments as described in the
Pollution Prevention Awareness Plan). i
SNL waste minimization personnel solicited ideas and requested volunteers for
pollution prevention projects from line organizations and MinNet representatives.
Two laboratories, the MFRL and the Geochemistry lab, were chosen as candidates
for PPOAs. The selection was due in part to the fact that the MFRL and
Geochemistry lab were representative of many other laboratories at SNL. The two
laboratories also were suitable to demonstrate different approaches to the PPOA
process. The pollution prevention assessment teams were comprised of the MinNet
representatives, the laboratory personnel, engineers that work closely with the
lab, and EPA contractor personnel. This team approach afforded SNL personnel the
opportunity to learn about PPOAs by actively participating in the process.
-------
PROCESS REVIEW
Background
The MFRL typically repairs printed qircuit board assemblies, wiring and box
assemblies (mother boards) for use in satellite systems. Repairs usually involve
implementing design changes and modifications by adding or replacing electrical
components. Occasionally, repairs involve replacement of faulty electrical
components. Of approximately 1100 repair requests processed from October 1990
to September 1991, 80 percent involved ;boards while the remainder was roughly
divided between boxes and cables. These repairs usually involve soldering of new
resistors, capacitors, transistors, etc. Due to a recent change in workload,
MFRL also repairs similar assemblies for ground equipment.
A work repair request is submitted for each electronic assembly needing
repair. MFRL staff log in the board and gives it an initial inspection. The
part is provided to the technicians for|repair. After the repair, the board is
again inspected to assure all work was adequately completed. The process flows
for types of repairs inside and outside ,the MFRL are presented in Figures 2 and
3, respectfully.
Currently, about 70 percent of the electronic boards are destined for
satellite applications and the remainder are used in miscellaneous ground
equipment. Satellite systems cannot be repaired once deployed (except by an
expensive space shuttle mission); the final product must be of superior quality.
Approximately 683 pounds per year .of waste are generated from the MFRL.
Figure 4 presents the waste generation data. Bulk solvent accounts for a
majority of the waste generated. The distribution of the other waste generated
at the MFRL is shown in Figure 5. ; Other waste streams include: solvent
contaminated lab trash; rinse water; conformal coating waste; isopropanol; solder
and lead scraps; potting compound waste; isopropanol contaminated lab trash;
adhesive contaminated lab trash; and flux contaminated lab trash. Wastes and
input materials are primarily related to board repair, but a.portion of these are
due to repair of box assemblies and cables. The total waste generation on a per
unit basis is approximately 0.62 Ib (0.07 Ib excluding bulk solvent). Waste
generation can vary significantly from one repair to another.
While spent TCA from the vapor degreaser is the largest waste stream at the
MFRL, it was decided by SNL that the assessment would focus on other supporting
operations and waste streams. This was due in part to the fact that the vapor
degreaser was scheduled to be replaced within 2 to 3 years. Limited information
was available on the replacement system and the solvent(s) to be used for
defluxing were not determined. Regardless of the cleaning method, the remaining
waste streams would still exist. Additionally, sufficient guidance exists in the
-------
Material Inputs
Process Flow
Waste Outputs
Sctdtr, Flux, Wtdca, Kim
Soldtring Iron Tip*, Adln*iv»
Pntfef* Swmbtjdm W7p«»,
Conform*! Catting, Strata,
Kim tWp*«, Glovts
Repair
Requested
SUfl
Logs In Board
SUH Perform
Ropairs
SUH Cleans
Board (at bonch
and/or using
vapor degreasar)
Repairs
Complatod?
Soldtr, Flux, Wick*. Kim
Soldtring Iron Tlf* (S W-)
Flux, Kim MTpw, Swato {0.73 tfyr.)
Adht*lv», Kim Won, Swrtx (5 *V-j^\
Sptat Pnlutt (4O-M giL/yr.)
Swtbt, Kim Wlp»f, Glov
No
Yes
inspector
Examines Board
Repairs
Correct?
No
Yes
Board
Adequately
Cleaned?
No
Board
Previously
Conformal
Coated?
No
Yes
Staff Applies
Conformal
Coating
Inspector Examines
Conformal Coating
_L
Coatlng
Properly
Applied?
Dritd/Expind Conformul Coftiny,
Swtti*,Klm
No
.Yes
Repaired/ Finished
Board Returned to
Engineer
Figure 2. Electronic Board Repair Within MFRL
-------
Material Inputs
Process Flow
Waste Outputs
Ba*rd L+»v»f UFFtL Control
Pnftt*, Wfttr, iMoproptnol
Conform*/ Catting. Swtbt,
Engineer Tests
Board ;
Board Performs
Adequately?
Unas*imbl8d
Syatam Off-sKa
to Subcontractor
Subcontractor
Claans i
UnasMmblod
Syatam I
Subcontractor
Applies Conforms!
Coating i
Unassembled System
Returned to SNL
(or Assembly
and Testing
Contaminated Pntiti,
Wttfr, Itoproptnol
Figure 3. Electronic Board Repair Outside MFRL
-------
current literature regarding pollution prevention and vapor degreasing. Focusing
on the other waste streams would, generate new ideas and concepts directly
pertaining to research and development operations.
603.09
79.97
E3 Other wasta !
• Bulk solvent (Prelete)
Figure 4. Total Annual Waste Generated At MFRL (Ibs)1
31.08
17.7
6.05
7.88
3 Solvent lab trash
• Pb contaminated water
n Conformal coating waste
53 Isopropanol
O Solder and lead scraps
E3 Potting compound waste
EH Isopropanot lab trash
S3 Adhesive lab trash
E3 Flux lab trash
5.28
Figure 5. Quantities of Other Wastes Generated at MFRlJ (Ibs)1
The waste streams identified were given a priority ranking. ! Due in part to
their annual quantities being the largest, solvent contaminated lab trash had the
highest rank and rinse water had the second highest. The priority rating
criteria used and the ranking of other waste streams is given in Appendix A
(Worksheet 6). ,
1 Based on chemical disposal information from 8/12/91 to 7/21/92.
7 ;
-------
SNL personnel currently segregate flammables or flammable-contaminated lab
trash (e.g. flux or isopropanol contaminated lab trash) from other waste streams.
Flammable waste is placed in a specially marked container in the storage room.
All other waste is placed into individual ziplock bags, labeled, and placed in
a container for non-flammables in the storage room. If flux lab trash is also
contaminated with TCA it is combined with any solvent contaminated lab trash.
Board Repair
The repair of printed circuit boards involves such operations as soldering,
cleaning, use of adhesives, removal and replacement of conformal coating.
Although SNL is not a Department of Defense facility, it has
voluntarily decided to implement applicable military specifications (e.g., MIL-
STD-2000A, Standard Requirements for Soldered Electrical and Electronic
Assemblies) for repairs to electrical assemblies (Department of Defense, 1991).
• New leads on replacement components are dipped into a molten bath of solder
(63 percent tin, 37 percent lead) to apply a thin layer. This operation is
referred to as tinning. Solder (in the form of metal bars) is melted in the pot
for makeup. Tinning is carried out in the vapor degreasing room in a small
(approximately 1 pint) solder pot that is continuously heated.
Boards are repaired with wire solder. Solder forms an intermetallic bond
which secures the components onto the board. A mildly activated resin type flux
is also used while soldering. This flux conforms to Federal Spec. QQ-S-571E,
Type RMA. Resin (sometimes referred to as rosin) fluxes contain activators which
increase the wetting ability of the solder by removing oxides present on the
surfaces to be soldered (United Nations Environment Programme, 1991). Solid flux
is contained in the core of the solder w|re and applied through use of the wire.
Additionally, it is applied in liquid form by small applicator bottles directly
to the area being soldered. Mil-STD-200pA dictates that the solder type must be
either resin activated (RA) or resin-biildly activated (RMA) (Department of
Defense, 1991). !
»
Cleanliness for aerospace applications is critical. Board and assemblies
must be free of foreign materials including grease, dirt, flux residue, solder
splatter, solder balls, insulation residue, and wire clippings (Department of
Defense, 1991). Residual flux can affect corrosion, adhesion of conformal
coatings, and performance. Residual flux has the appearance of a brownish stain
on the board. Currently, the boards are|cleaned with a commercial solvent known
as Prelete. Prelete primarily contains 1,1,1, trichloroethane (TCA). Cleaning
is accomplished at the work bench where; soldering is performed or in the vapor
degreaser. Some technicians clean after each solder while others try to clean
after all or several repairs are complete. Regardless of these two approaches,
the flux should only remain on the board for a specified period of time. If the
flux is not removed promptly, it may be difficult to remove and in extreme cases
a biological growth (mold) may develop.
Adhesives are used to place electronic components on the printed circuit
boards. Adhesives are a two part epoxy resin. The types of adhesives at MFRL
include both conductive (contain silver) and non-conductive (rubber or epoxy).
8
-------
The epoxy resin is a two part resin. .: .
Conformal coating is usually applied by an offsite contractor on tested
boards after manufacture or repair. This polyurethane coating protects the board
from contamination by foreign materials. If repair is required on a board
previously conformal coated, the coating in^proximity to the area to be repaired
is removed by heating. After repair, the coating is applied with the sharpened
end of a wood swab stick by SNL staff. I
Input materials used for repair of boards include solder, flux1, bulk solvent,
cleaning materials, and adhesives. The cleaning materials include tissue wipes,
cotton swabs, brushes, etc.; Waste streams generated from board repair include
bulk solvent, solvent contaminated lab trash, conformal coating !wastes, solder
and lead scraps, adhesive lab trash, and flux contaminated lab trash.
Approximately 17.7 pounds per year of solvent (TCA) contaminated lab trash are
generated by the MFRL. This waste is classified as a F002 waste and primarily
consists of used wipes and swabs from spot cleaning of boards at the work
benches. Approximately 7.9 pounds per year of conformal coating wastes are
generated. This waste contains used applicators (sharpened swab'sticks), paper
towels, and unused product.i A little over 5 pounds per year of solder and lead
scraps are generated from soldering. These wastes are hazardous due to the lead
content and are classified as a D008 waste. Nearly 5 pounds per year of adhesive
lab trash result from affixing electrical components to boards; Less than 1
pound per year of flux contaminated lab trash is generated. i
Box Repair !
[
Repair of assembly boxes is occasionally required. These repairs may involve
similar operations and waste generation as board repair, but the cleaning process
varies. Since the boxes are generally too large for cleaning in the vapor
degreaser, the boxes are cleaned with successive rinses of TCA, isopropanol, and
deionized water in trays in ;the fume hood. Some adhesives are also used to hold
down wiring harnesses. ;
Waste streams unique to the repair of box assemblies are isopropanol, rinse
water, and isopropanol lab trash. These waste streams are generated from
cleaning (defluxing) of soldered connections. Isopropanol used to rinse box
assemblies is collected in a tray and may be used for successive rinses. Once
the isopropanol is spent or the repair is complete the isopropanol is poured back
into the original container,ar\d lab packed. Rinse water is similarly generated
and managed. Isopropanol lab trash is sealed in small plastic bags and placed
in a flammables container in the storage room. !
Cable Repair '
Cables may need to be fabricated or repaired by MFRL. Typical repairs
include soldering of cable wires to the correct pin connections! and/or use of
potting compound. Potting compound is a resin that bonds the cable wire,
insulation, and pin connector together and encapsulates the soldered connections.
-------
Input materials unique tc ,. aiple repair include potting compound. Unused
potting compound and the associated lab trash from applying the epoxy resin
represent additional waste generated at the MFRL.
10
-------
ASSESSMENT ; '
, i
The assessment team visited the two rooms (repair room and vapor degreasing
room) and the storage room for the MFRL. During the assessment phase of the
PPOA, several options were identified for each waste .stream; these are discussed
in this section. i
i
Solder and Lead Scraps ,
The options under consideration for this waste stream include use of lead-
free solder or recycling of the solder. Tin-rich, lead-free solders such as
95Sn-5Sb (wt.%) and 95.5Sn-4.0Cu-0.5Ag look promising (Vianco, et. al., 1991).
At this time, all approved solders under MIL-STD-2000A are tin-lead alloys
containing either 40, 38, or 37 percent lead (Department of Defense, 1991).
Recycle of the solder is possible if the solder and lead scraps can be
effectively segregated from other lab trash. Solder could be sent to
manufacturers for reuse, but this would probably not be economically feasible due
to transportation costs, unless the waste is accumulated over a very long time,
or if several electrical repair labs consolidate this waste streani. In addition,
vendors may be reluctant to deal with shipments of less than a drum. A simple
way to recycle would be to place solder scraps into the solder pot. Any
impurities from the scraps would float to the top as does the impurities already
in the pot from tinning. The impurities are currently skimmed off the top to
maximize pot life. It is estimated by the MFRL supervisor that about 10 percent
of the solder and lead scraps could be effectively segregated and recycled into
the solder pot. i
Flux Contaminated Lab Trash
j
Potential pollution prevention measures that were considered included: use
of low flux or fluxless solder and the addition of isopropanol to thickened flux.
One of the current flux vendors was contacted about the availability of
alternative fluxes. This vendor mentioned a 10 percent solids flux already
approved by the military and a 3 percent solids flux that is anticipated to be
approved shortly. These new fluxes reportedly have low resistivity and are non-
corrosive. If the solids that remain are not significant, cleaning may be
eliminated. These fluxes have less solids than the current flux (35 percent
solids) and would be easier to clean. The quality standards for these electronic
components would most likely, still dictate defluxing, but if the bbards, etc,, are
cleaner initially, alternative cleaning methods ( such as isopropariiol bath/rinse)
may be more feasible.
11
-------
Some lab trash is the result of flux thickening in the wide mouth applicator
bottles used to apply flux before tinning. Flux contains isopropanol and tends
to thicken as the isopropanol evaporates:. When the flux becomes too thick, the
flux is discarded and the jars are cleaned out with TCA. Addition of isopropanol
may reconstitute the flux, but the effect of adding too much or too little
isopropanol is unknown. Instead of cleaning with TCA, the jars should be cleaned
with the used isopropanol.
Adhesive Contaminated Lab Trash |
The main wastes consist of electrostatically dissipative gloves, used
applicators, and unused material. Technicians use gloves that cover the entire
hand up to the wrist. Finger cots anre available and have been used by
technicians during training. Only a small portion of the applicator comes into
contact with the adhesive. If all technicians broke off the contaminated portion
of the wood stick, the amount of waste would be reduced.
Only a small fraction of the 1 cubic centimeter tubes the product comes in
is actually used. Smaller tubes or reusable tubes would be helpful. Some waste
is generated from product exceeding the expiration date. The MFRL already shares
orders with other labs and puts out memorandums indicating the availability of
excess material to other areas of SNL. The problem with the expiration date is
that the supplier's minimum order is |too large. SNL was unsuccessful in
negotiating this point with suppliers; an alternative approach would be to ask
for the same amount shipped in installments over several mon,ths. Each shipment
of product would need to have sequentiial expiration dates in order for this
option to work. :
12
-------
TCA
The current system uses a basket with a mesh which is much smaller than
required for the majority of the parts cleaned in the MFRL. Use of a larger mesh
basket would reduce dragout. The technique that operators use to clean boards
varies. Some use small bottles at their workbenches to spot clean after each
connection or component is soldered and clean in the vapor degreaser after
repairs are complete; others use the vapor degreaser for all cleanings at once.
Cleaning in the vapor degreaser is preferable since the lab trash associated with
bench cleaning is avoided.
The boards are cleaned, tested and sent offsite for conformal coating by a
contractor. The contractor also cleans the boards prior to applying the
conformal coating. The boards must be cleaned at SNL to facilitate inspection.
If the boards could be inspected and tested in a way that did not cause further
contamination by grease, oil or dirt, the boards would not require the additional
cleaning before conformal coating. \
In the near future, TCA will be phased out due to its ozone depleting
properties and a new cleaning system will be installed which uses a substitute
cleaner. The new cleaner will probably be a terpene based solvent. Additional
evaluation of alternatives or of the operation of the current vapor degreaser is
beyond the scope of this project. \
Solvent Contaminated Lab Trash
Several options were identified and evaluated which concerned the solvent
contaminated lab trash. Bench or spot cleaning could be eliminated by all
technicians as long as the flux is cleaned in the vapor degreaser or equivalent
system within the time limit (30 min). Currently, one technician does spot
cleaning while the other technician and supervisor only use the vapor degreaser.
Spot cleaning facilitates inspection but does little to remove the flux
contamination; instead it is thinly scattered across the board. iThe technician
that spot cleans still dips ;the board in the vapor degreaser once the repair is
complete. i
Eliminating spot cleaning would not result in a significant increase in the
use of the vapor degreaser. Since spot cleaning does not; fully remove
contaminants, the amount of flux contaminants going to the vapor degreaser is
about the same and no change in the bath life or usage of Prelete is expected.
It was suggested that foam-tipped swabs be used instead of cotton swabs; the
foam ones could possibly be cleaned and reused. According to the lab supervisor,
foam-tipped swabs were usedHn the past and discontinued because they left too
much debris on the boards. Breaking off the ends of the wooden swabs and
: 13
-------
segregating the TCA contaminated end from the clean end needs; to be practiced by
all technicians. Compaction of TCA contaminated lab trash was discouraged by the
disposal people because of the possible formation of free liquids. Another
option was to bulk the swabs. Currently, the waste at the end of each shift is
placed in small bags no matter what the volume is. Because of this, much of the
waste stream weight and volume is associated with packaging. The amount of waste
generated could be reduced if the swabs were bulked in a container within the
fume hood and bagged in one large bag weekly. This should not impose any
additional health or safety hazards or media transfer to the air from current
disposal practices.
Some solvent contaminated lab trash is generated from the cleaning of boxes.
Gloves and wipes are the primary wastes from this operation. Options similar to
the ones described for the repair of bpards would also be applicable to box
assembly repair, with the exception of eliminating bench cleaning for large
boxes. ',
Conformal Coating Wastes
Use of finger cots (rather than full hand gloves) and breaking off the unused
portion of the applicators can reduce the amount of waste generated. The
expiration date of the conformal coating can likely be extended by storing the
product in a freezer; this method of storage has yet to be evaluated.
Rinse Water
This waste should be analyzed to determine if it is actually a D008 waste
(i.e., > 5ppm lead). If it is not, the hazardous waste regulations would not
apply. Assuming the water is nonhazardous, it could be reused as a non-critical
rinse for glassware cleaning in MFRL or other labs. In addition, the rinse water
is potentially applicable to a wide variety of other non-potable uses. The water
could be poured through a filter (to remove solids such as solder scraps) and
into the original container. A new label! would be required on the container that
identifies the water as not potable. It should be mentioned that test results
indicating significant levels of lead render this a non-viable option.
Isopropanol |
A very small portion of waste isopropanol from the cleaning of box assemblies
could be reused to clean out flux that has thickened in containers. Instead of
being placed back in the glass jars and lab packed, the used isopropanol could
be bulked in 5 gallon or larger containers. A waste exchange should be explored
to see if other areas at SNL may have a need for the waste isopropanol, such as
non-critical cleaning. |
Isopropanol Contaminated Lab Trash
Options discussed with SNL personnel included use of brushes or wipes that
are reusable instead of disposable. • SNL could also re-evaluate whether
isopropanol contaminated trash always meets the definition of an ignitable
hazardous waste. Determination of when the lab trash is characteristically
14
-------
hazardous may be subjective.
Potting Compound
As much as possible, several cable repairs should be scheduled
simultaneously. This will maximize the usage of mixed potting compound.
Technicians should try to minimize the amount of potting compound mixed for each
repair. Storing extra mixed potting compound in the freezer can extend the
useful life of the product.: Technicians should also try to minimize the area
being repaired to what is actually necessary.
15
-------
FEASIBILITY OF OPTIONS :
The pollution prevention options evaluated in detail during the feasibility
analysis are summarized in Table 1. Capital investment was determined by
consulting equipment supply catalogs. Net operating cost savings were based on
disposal costs and/or reductions in raw material costs. The payback period was
calculated by dividing the capital investment by the cost savings. The rank of
each option was determined qualitatively based upon annual cost savings,
implementability of the option, and payback period.
Test/Reuse Rinse Water j
Testing of the rinse water would pr!obably reveal that it is not. an actual
D008 waste. Once this waste stream is determined to be non-hazardous, it could
be used for other non-potable purposes.
The cost of testing is estimated to be $50 assuming purchase of two test
kits. The samples would be taken by f|FRL personnel and sent to a certified
laboratory for analysis using an appropriate method, such as SW-846 Method 6010,
7420, or 7421 (U.S. EPA, 1986). This price may be reduced if analysis can be
performed onsite by another organization within SNL. The change in disposal and
transportation costs results in a net annual savings of $139.50. The payback
period for this option is 0.36 years.
Eliminate ZipTock Bags ;
i
Nonflammable contaminated laboratory trash is placed in ziplock bags so it
can be carried to a 30 gallon container in the storage room. The waste container
is lined with a plastic bag which is removed when full and transported to the
waste disposal area. Each ziplock bag is labelled with a bar code for tracking
purposes. At this point the bag is lab packed (combined in special containers)
with other wastes. The ziplock bags contain mostly air. By keeping a lined 20
gallon polyethylene container in the vapor degreaser room, the use of ziplock
bags could be eliminated. The disposal people already pick up similar containers
at SNL.
The cost of the 20 gallon container was priced at $31.20. The change in
disposal and transportation costs is estimated to be $28.40. The raw material
costs savings from not having to purchase ziplock bags for this purpose is
estimated at $100. With a net annual savings of $128.40, the payback period for
this option is 0.24 years. .These savings do not include reductions in waste
management costs produced by no longer bar coding and tracking each individual
ziplock bag. When considering these savings, the payback period will be much
shorter.
-------
Break Off Swabs
By breaking off the contaminated ends of swab sticks, the amount of hazardous
waste generated can be reduced. As long as the uncontaminated end is long
enough, it could be reused by the technician. It is estimated that the amount
of laboratory waste resulting from swab use could be reduced by 80%.
Approximately 100 swabs perj year could be eliminated by reusing'the clean ends
of broken swab sticks.
No capital costs are associated with this option. The estimated disposal and
transportation cost savings are estimated at $20.55. The change in raw material
cost from purchasing less swabs is $1.73. The net annual savings would be
$22.28. Since there are no capital costs, the payback period would be zero
years(savings realized immediately).
; i
Eliminate Bench Cleaning \
Lab trash is generated when bench cleaning is performed to deflux soldered
connections. After the boards are repaired they are cleaned in the vapor
degreaser, regardless of whether they were bench cleaned or not. Elimination of
the bench cleaning step would reduce the amount of solvent and flux contaminated
lab trash generated. In addition the number of wipes and swabs;expended would
be less. i :
There is no capital costs associated with this option. The disposal and
transportation cost savings from this option are estimated to be $63.11. Raw
material cost savings are $26.15. The expected net annual savings is $89.26 with
a payback period of zero years. :
17
-------
C/)
»-4
CU
o
m
1 PREVENTI!
O
1
^J
g
ULt
o
gg;
co
t—t
LU
_J
•Mo ?
CO 4-» «—
C£ JZ ***
_J S
"o -g
J.SC
S-fci
a. a.
ID
».£
•£'i t_
4-» CO >*
ca ^^
4-> CU CO
cu a. o
zoo
Capital
Investment
$
g
i
*sJ
B^ 1
CO O U
z a. a.
g
Is
"8
*-* *#-
§
1
a.
c
_o
- tr»
— * 4-f
is-
to
to
o
o
in
Os
to
o
o
0
in
1
1
an
c.
cu
4J
CD
CU
CO
c
o:
cu
4-*
ca
3
CU
8
cu
CO
3
CU
4^
CO
CU
1—
™
0
o
eo
S
c.
L.
*CU 4-1
§_ca
"3
co ee
c.
CU t
a. a.
co ca
- y a L.
»J= 3 U
_IZ CO O) CO
co co c ~a
ca t-— C ~a
t- 4J 4J 3 S
-I-N
eu 'co o •— cu
> CU •»- 4J TJ
— • -C C 4J — *
o -a o o o
co ca u a. ca
CO
8
"a.
fij
cu
ca
c
'e
UJ
o
00
r\j
CVI
(M
o
1
cu cu
8CA
3
c- cu
III
c a "
o — • o
CO »
L- o: o
CU 1 CU
rt a* ***
-C
1 « CO
CU •• CO
4J CU I-
CO 4-» 4-»
J?"« D) -2
M ca c ~o
CO C. ••- C — •
L. 4J 4-» 3 O
4-> ' CO O C
^ O Q. CO
^} CD U & Q.
CO — « O O
— < : — • O I-
cu co a.
*-• > E O) O
C — I- C CO
CU (0 O •— •—
-* c^-5
o fl o g e
CO CO U Q. CD
J§
(O
en ,
^_
H-
o
ca '
cu
L.
m
o
~
<>
co
o
c_
1
a.
"cu "8
C 4J
CO CU
feT
a. cu
^
CO
"8
a
1
4-*
I
4-f
5 "«
— ' CO
0 t-
CO *J
eanirvg
o
1
cu
CO
cu
1
'I
ai
CO
-------
CROSSFEED TO OTHER DOE FACILITIES
Other DOE laboratories and facilities perform repairs on electronic
assemblies. The options described in this report could be implemented at other
locations. Given DOE's stated commitment to pollution prevention!, successfully
implemented options at SNL would be quickly disseminated to other locations.
19
-------
MEASUREMENT OF POLLUTION PREVENTION
The success of implemented pollutioji prevention options for the MFRL could
be easily measured since the waste quant;ities are tracked. The cost data for the
raw materials could be determined from previous purchase orders. Waste
quantities and raw material usage after implementation could then be compared.
ZO
-------
IMPLEMENTATION PLAN
Implementation of pollution prevention opportunities identified by the PPOA
is at the discretion of SNL. Breaking off the ends of swabs and eliminating
bench cleaning (see Table 1) could be implemented at any time by briefing the
technicians. Other options presented in Table 1 could be implemented in the near
future. Other ideas, such as changes in solder, flux, and cleaning solvent will
require additional planning and decision analysis before they can be implemented.
21
-------
RESEARCH DEVELOPMENT AND DEMONSTRATION NEEDS - |
I : ,
One approach to eliminating the use of TCA and other subsequent cleaning
solvents is through the use of low solids or non-clean flux. These types of
fluxes leave such an insignificant amount of residual that cleaning with solvents
is unnecessary. A research project designed to evaluate the performance of
boards repaired in this manner compared with boards cleaned in the conventional
manner should be initiated.
Lead-free solders need to be evaluated as a substitute for the traditional
63Sn-37Pb (wt. %) solder. A project conducted in the Metallurgy Department of
SNL, Albuquerque has examined the performance of three such solders. The
wettability of solders comprised of 95Sn-5Sb (wt.%), 95.5Sn-4.0Cu-0.5Ag, and
96.5Sn-3.5Ag were compared to that of 60Pb-40Sn on oxygen-free high conductivity
copper. Both RMA and organic acid (OA) fluxes were examined in the study. Both
the 95.5Sn-4.0Cu-0.5Ag and the 95Sn-5Sb alloys ^exhibited good wetting as compared
to the excellent wettability of the GOPb-koSn control solder. The wetting rates
and wetting times for the 95Sn-5Sb and ;95.5Sn-4.OCu-0.5Ag tin-rich, lead-free
solders were comparable to the control solder. The residue left by the water-
soluble OA fluxes was more evident than those from the RMA flux. This work
demonstrated that tin-rich, lead-free solders are viable contenders as solder
substitutes. In addition, it demonstrated the necessity of wettability testing
to evaluate the combined effect of solder substrate and flux. Other ongoing
research involves the solderability of structural and electronic joints and the
elevated temperature aging of the microstructure and solder-substrate
intermetallic layers of the tin-rich, lead-free solders (Vianco, et.al., 1991).
Much RD&D can be done for identifying and evaluating alternative cleaners to
TCA. The selection of cleaners can be influenced by the type of flux used (e.g.,
OA flux is water soluble while RMA and RA are not). Upon review of available
literature by SNL personnel, terpene-baSed cleaners such as Axarel 32 (Dupont)
and EC7R (Petrofirm) have been,identified as potential solvent substitutes. The
performance of these cleaners i needs to be evaluated in comparison to the
established cleanliness benchmark. i
i
Purchasing practices could be reviewed to try and find alternative methods
which would minimize waste generation due to input materials exceeding expiration
dates. The "just-in-time" purchasing used to quickly order supplies from vendors
with standing contracts has been implemented at SNL. However, unique and small
quantity supplies like the ones needed by the MFRL are not stock items in the
just-in-time system. Vendors simply will not stock items which are rarely
ordered and have short shelf-lives. The chemical exchange program at SNL has
been limited because most input materials used in the MFRL are unique to that
organization. Expansion of the chemical exchange and just-in-time purchasing
programs to all three Sandia locations and possibly other DOE facilities should
22
-------
be studied. Potential exci^ ifkners at c&r£ Sandia or DOE facilities should
be identified. While expansion would find other end users of similar products,
the logistics and expense could be prohibitive.
23
-------
RECOMMENDATIONS/CONCLUSIONS
Of the four options evaluated in detail, eliminating ziplock bags appears
to be the most promising. All of the options had payback periods of less than
six months. The waste reduction achieved from any of the options evaluated is
small, but they are easy to implement and savings could be realized quickly.
With respect to the applicability of the WREAFS PPOA process to small
research and development operations such as the MFRL and the Geochemistry lab at
SNL, the approach has shown to be an! effective pollution prevention tool.
Worksheets 1 through 9 of the Facility Pollution Prevention Guide proved useful
in the assessment. The PPOA process focuses efforts in a step wise fashion,
helping to organize information and ideas in a logical manner.
Due to the varied nature of research and development operations, certain
aspects of the process were made difficult. Since repair requests can require
varying levels of effort, and generate varying amounts of waste, normalization
of waste generation (i.e., waste produced per unit repaired) is difficult to
develop, and once determined, can be misleading. The initial cost effectiveness
of performing a PPOA on a laboratory thatigenerates small quantities of waste may
not justify the effort. Nevertheless, if options generated by the PPOA can be
implemented in other laboratories and facilities, the process may be cost
effective. The options discussed for the Geochemistry lab , in a separate
report, are more general in nature thanithose discussed in this report. Since
several options discussed in this report are related to specific waste streams
within the MFRL, their applicability to other labs is limited to those where
similar work is being performed. ,
The options identified in this report are presented only as examples of the
types of activities that could be identified using EPA's systematic approach to
pollution prevention for the individual organizations within SNL. The cost
effectiveness of conducting PPOAs for other SNL organizations should be examined.
An ongoing effort at SNL is to prioritize waste generators based on quantity
and/or type of waste generated. Implementation of options at SNL should be done
according to a prioritization ranking; those with the greatest potential for
pollution prevention done first. ;
24
-------
REFERENCES . .. • ;
: "- i
1. Facility Pollution Prevention Guide. EPA/600/R-92/088, U.S. Environmental
Protection Agency, 1992. j
2. Guides to Pollution Prevention: The Fabricated Metal Products Industry.
EPA/625/7-90/006, U.S. Environmental Protection Agency, 1990.
i
3. Military Standard: Standard Requirements for Soldered Electrical and
Electronic Assemblies. MIL-STD-2000A, Department of Defense, 14 February
1991. i
4. Montreal Protocol 1991 Assessment: Report of the Solvents, Coatings, and
Adhesives Technical Options Report. United Nations Environment Programme,
1991. : ;
5. Sandia National Laboratories Waste Minimization and Pollution Prevention
Awareness Plan. Sandia National Laboratories, December 31, 1991.
6. Test Methods for Evaluating Solid Waste, Third Edition. SW-846, U.S.
Environmental Protection Agency, 1986. ;
7. Vianco, P. T., F. M. Hosking, and D. R. Frear. Lead-Free Solders for
Electronics Applications: Wetting Analysis. Electronic materials processing
congress (4th), Montreal (Canada), Sponsored by U. S. Department of Energy,
Washington, DC, August 1,991.
25
-------
APPENDIX
PPOA Worksheets
26
------- |