v>EPA
United States
Environmental Protection Agency
^ Office of
jr Research and Development
National Human Exposure Assessment Survey
(NHEXAS)
Region
Quality Systems and Implementation Plan
for Human Exposure Assessment
Notice: The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), partially funded
and collaborated in the research described here. This protocol is part of the Quality Systems Implementation Plan (QSIP)
that was reviewed by the EPA and approved for use in this demonstration/scoping study. Mention of trade names or
commercial products does not constitute endorsement or recommendation by EPA for use.
Research Triangle Institute
Research Triangle Park, NC 27079
Cooperative Agreement CR 821902
Standard Operating Procedure
NHX/SOP-820-001
Title: Certification of Standard Weights
Source: Research Triangle Institute
U.S. Environmental Protection Agency
Office of Research and Development
Human Exposure & Atmospheric Sciences Division
Human Exposure Research Branch
378herb00.pdf ~ R820-001.pdf

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STANDARD
RESEARCH TRIANGLE INSTITUTE
NHX/SOP-820-001
OPERATING
POST OFFICE BOX 12194
Page 1 of 3
PROCEDURE
RESEARCH TRIANGLE PARK, NC 27709-2194
TITLE:
SOURCE:
STANDARD OPERATING PROCEDURE FOR CERTIFICATION OF
STANDARD WEIGHTS
Research Triangle Institute
Post Office Box 12194
Analytical and Chemical Sciences
Research Triangle Park, NC 27709-2194
AUTHOR(s):
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Date:
Date:
Date:
APPROVED BY:
Principal Investigator:
QA Officer:

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STATUS:
IN PROGRESS: ~

DRAFT: ~

FINAL VERSION: |X]
REVISIONS:
No. Date
No. Date
++
o
6
1
7
2
8
3
9
4
10
5
11
J Effective date of this version is the date of the last approval signature;
revision 0 is the original version.

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NHX / SOP-820-001
Revision 0
Page 2 of 3
CERTIFICATION OF STANDARD WEIGHTS
TABLE OF CONTENTS
Section	Page
1.0 General		3
2.0 Scope of Procedure		3
3.0 Procedure		3
4.0 Documentation 		3

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NHX / SOP-820-001
Revision 0
Page 3 of 3
1.0 GENERAL
This Standard Operating Procedure describes the guidelines used in having weights
calibrated against standards traceable to the National Institute of Standards and Technology,
NIST (formerly the National Bureau of Standards, NBS).
2.0 SCOPE OF PROCEDURE
Any laboratory certified by the U.S. Department of Commerce National Institute of
Standards and Technology can calibrate the weights. The N.C. Department of Agriculture,
Standards Division, (919-733-4311) is recommended by the ACS QA staff. The QA officer
maintains a set of weights that are certified yearly. A yearly calibration is recommended for
other standard weights.
3.0 PROCEDURE
Before weights are taken to the laboratory, obtain a purchase order. The weights can
be hand delivered or shipped by RTI. Other information needed is the density of the
weights and the type of tolerance test you want conducted.
Make an appointment to have the weights calibrated. It takes at least a week to have
the calibration completed. You should receive the following documents:
1.	Report of calibration.
2.	A copy of Standards Laboratory Certification.
3.	Statement of Traceability.
4.0 DOCUMENTATION
All certificates will be placed in a spiral notebook. The notebook will be maintained
by the QA program staff.

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