A diaphragm can be exposed to a number of media and expected to operate in all of them. When exact exposure is known, testing should be conducted using the fluid in question. In many instances, however, standard test fluids are used for evaluation and are specified by many testing procedures. Some of the more common test fluids are listed as follows:
- TEST FLUIDS:
- ASTM #1 OIL: A low-swell, petroleum-based oil.
- ASTM #2 OIL: A medium-swell oil.
- ASTM #3 OIL: A standard oil containing aromatic fractions with more effect on swell than #1 or #2.
- Reference Fuel A or MIL-H-3136 Type 1: A petroleum fuel (iso-octane) with a mild swelling effect on elastomers.
- Reference Fuel B or MIL-H-3136 Type III: A test fluid composed of 70% iso-octane and 30% toluene by volume.
- Reference Fuel C: A test fluid composed of 50% iso-octane and 50% toluene by volume.
- Reference Fuel D: A test fluid composed of 60% iso-octane and 40% toluene by volume.
- Toluene or Toluol: An aromatic hydrocarbon solvent.
- Xylene or Xylol: Similar to toluene, except its effect on swell is less.
- TT-S-735-Type II, Amend II: A high-swell fuel containing aromatic fractions composed of 60% iso-octane, 25% toluene and 15% xylene.
- SAE NO. 10, 20, 30, 40, or 70 OIL: These are straight petroleum-based oils and are commonly used to lubricate automobile engines.
- Gasoline, "Gasohol" and Sour Gas: Various types and mixtures required to meet industrial needs.
- Ethylene Glycol: Mixed with water for testing swell.