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 243 of 460

FED-STD-791D

handling and storage precautions, emergency treatment and measures, and spill practices

of each chemical are explained.

5.2 Test sheets (3), rubber standard, type as required by the specification,

approximately 2.5 H5.1 H 0.19 cm. Samples of synthetic rubber stock should not be

older than 6 mo.

5.3 Alcohol, ethyl or methyl, anhydrous [1,3,0].

5.4 Filter paper.

5.5 Distilled water.

6. PROCEDURE

6.1 Determine the water displacement of each test sheet to the nearest 1 mg by

weighing each sheet in air, then in distilled water at 24� " 3�C, recording the weights,

and computing the difference between the weight in air and the weight in water for each

sheet (see 7.1).

6.2 Fill container with sample, using the following:

a. For liquid sample: Approximately 20 mL of sample for each gram of total

weight of test sheets.

b. For grease sample: Sufficient sample to fill container completely.

6.3 Blot dry each test sheet with filter paper, then immerse sheets completely in

sample in container. For grease samples, immerse test sheets vertically, with 5 cm edge

uppermost, and cover the container.

6.4 Store container in oven at 70� " 1�C (158� " 2�F) for 168 " 0.5 h

(approximately one week). For liquid samples, maintain a ratio of 20 mL of oil to each

gram of test sheet. Make up oil must be the same temperature as the test fluid when

added. For grease samples, check daily (except weekends), that the samples are in

complete contact with test sheets and close any voids by using a spatula.

6.5 At the end of the storage period, cool the sample to 24� " 3�C. Then clean

test sheets as follows:

a. Remove test sheets from sample and wipe them to remove most of the adhering

sample.

b. Dip sheets in alcohol and wipe or blot them dry, using filter paper (or soft

cloths). NOTE THE TIME.

6.6 Within 5 min of drying test sheets, redetermine the water displacement of

each sheet as specified in 6.1.

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