NVLAP LAB BULLETIN NUMBER: LB-93-2016 PAGE: 1 of 2 

DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

National Voluntary Laboratory Accreditation Program

ISSUE DATE:

March 04, 2016 

LAB BULLETIN 

NUMBER: LB-93

LAP: Asbestos - PLM

SUBJECT: Use of Computerized Systems for the Recording of Bulk Asbestos Analysis Data

The purpose of this Laboratory Bulletin is to clarify NVLAP requirements regarding the use of 

computerized systems for the recording of bulk asbestos analysis data. 

Laboratories must document that analyst(s) are actually gathering all the required data from every single 

sample by PLM examination. This includes the optical properties as measured by the analyst, including 

the refractive index determined by using dispersion staining colors or Becke line. The use of 

computerized systems that populate default values for optical data based on the macroscopic 

identification of the asbestos in the sample or the refractive index of the oil does not meet these 

requirements. 

A blank entry field with a drop-down menu for manually entering or selecting the measured results (data), 

defined in the clause 5.10.2 in the NIST Handbook 150-3 Checklist (REV. 2011-02-18) below, obtained 

from the actual observation made by PLM examination may be allowed, provided the analyst is utilizing 

the real test data against the information built in the laboratory’s computer system to determine the 

asbestos type investigated. 

In May of 1999, Lab Bulletin LB-3-1999 was issued to clarify NVLAP requirements for the recording of 

bulk asbestos analysis data. That Lab Bulletin stated: 

It has been reported that some of the NVLAP Bulk Asbestos Analysis laboratories are using a 

“default” system for recording the optical measurements performed on fibers detected in bulk 

building materials. A “default” system is a computerized system whereby an analyst enters his or 

her best guess as to the asbestos type a fiber may be and the computer then enters all the required 

optical data, without the analyst ever performing the optical measurements. NVLAP assessors 

are told that the analyst then performs the optical measurements and edits the screen if his or her 

data is different than the default values the computer has entered. 

The information in the 1999 Bulletin was incorporated into the 2006 version of NIST Handbook 150-3, 

Bulk Asbestos Analysis in the following clauses. 

5.4.5 Computerized systems that provide default optical measurements do not meet NVLAP 

requirements. Laboratories shall have documentation to show that analysts are measuring optical 

data by PLM examination. 

5.10.2 If original data are entered using a computer, analysts shall type the determined refractive 

indices into the corresponding fields. A set of fixed default values of refractive indices for 

respective asbestos types automatically generated by the computer is not acceptable (see 5.4.5). 

The following language in the NIST Handbook 150-3 Checklist (REV. 2011-02-18) differs from the 
NVLAP LAB BULLETIN NUMBER: LB-93-2016 PAGE: 2 of 2 

language in Handbook 150-3, but addresses the requirements. 

5.4.5 The laboratory shall determine the identification of fibrous materials by measuring the 

optical properties (see 5.10.2). 

5.10.2 The laboratory shall record the following data for the asbestos type(s) identified by PLM 

examination: 

a) morphology; 

b) color and pleochroism; 

c) indices of refraction (nD) parallel and perpendicular for each asbestiform mineral; 

d) birefringence; 

e) extinction characteristics, including measurement of extinction angles, if observed; 

f) sign of elongation; 

g) estimated concentration of asbestos; 

h) temperature at the workstation at the time of analysis; 

i) result of the analysis. 

This bulletin should be maintained with your copy of NIST Handbook 150-3 until the next 

edition of the handbook is released. Questions regarding the bulletin should be directed to 

Hazel M. Richmond, NVLAP Program Manager, at 301-975-3024, or hazel.richmond@nist.gov.