FED-STD-791 Lubricants, Liquid Fuels, And Related Products, Testing Method OfThis test method standard is composed of standard test methods for sampling, inspecting and testing lubricants, liquid fuels and related products. It is issued pursuant to the Federal Property and Administration Services Act of 1949, as amended and its application to the purchase of commodities referred to herein is mandatory on all Federal agencies.

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'�NOTE:This draft dated 15 April 2006' by DasH - Page 350 of 460

FED-STD-791D

test oil average rating

Relative rating, percent =

* 100

reference oil average rating

8. REPORTING

8.1 Report the percent relative rating (see 7.3).

where:

P = load carrying ability (or scuff limited load) of the lubricant, N/cm (lb/in).

K = Ryder gear machine constant (4.1.1).

L = Load oil pressure, gage Pa (psig).

W2 = effective tooth width, cm (in).

8.2 Calculate the percent relative rating using the following formula:

test oil average rating

Relative rating, percent =

* 100

reference oil average rating

9. REPORTING

9.1 Report the percent relative rating (see 7.3).

10. PRECISION

10.1 Repeatability. Results from one apparatus and operator should be

considered suspect if the relative ratings differ from their mean by more than 10%.

10.2 Reproducibility. Results from different apparatus and/or operators should

be considered suspect if the relative ratings from each apparatus and/or operator differ

from their mean by more than 5%.

Method prepared by:

Navy - NAPC - l986

349