ASTM D4293 Specification for Phosphate Ester Based Fluids for Turbine Lubrication
4. Significance and Use
4.1 This is a specification to define the requirements of fire resistant fluids for use in turbine lubrication. This specification defines phosphate ester fluids which will give satisfactory lubrication performance in a turbine engine. However, it is possible that phosphate esters that do not meet this specification may give adequate performance in the field.
4.2 Fire resistant fluids are more difficult to ignite and show little tendency to propagate a flame. The term "fire resistant fluid" does not mean that the fluid will not burn.
4.3 The normal fluid operating temperature will be in the range of 54 to 65°C and will experience a maximum temperature of about 93°C during flow across the turbine bearings whose housing temperature may be as high as 343°C.
5. Safety Precautions
5.1 The fire tests are used to measure and describe the properties of the phosphate esters in response to heat and flame under controlled laboratory conditions and should not be considered or used for the description or appraisal of the fire hazard of the fluids under actual fire conditions.
5.1.1 Fires that have occurred in operating turbines have usually been caused by fluid or vapors contacting hot surfaces. For example, fluid that may spill and be absorbed into unprotected thermal insulation can experience an exothermic reaction with resultant, potential rapid temperature increase. The ignition of the absorbed fluid can occur at temperatures below the fluid autoignition temperature. Thus, the high autoignition temperatures of phosphate esters have relevance to turbine lubricant fire hazards. Likewise,the SAE Aeronautical Material Specification 3150C tests are relevant to the particular hazards in turbine lubrication.
5.2 Conducting tests for fire properties such as Test Method D92 SAE AMS 3150C, could result in a serious fire or explosion. It is recommended that only experienced personnel run these tests.
5.3 Fumes generated by the above tests may be hazardous from the standpoint of both inhalation and skin irritation. Therefore, the Test Method D92 should be conducted so that all fumes and vapors are contained in a draft-free shield in a hood. High pressure spray flammability tests should, if possible, be remotely controlled from an area outside of or isolated from the test room, or if necessary, by an operator(s) provided with protective clothing and breathing apparatus with safety glasses or face shields, or both, appropriate to the test environment.
5.4 Because SAE AMS 3150C test pressures are controlled at 6.9 MPa (1000 psi) all equipment must be maintained carefully, checked for leakage before each test, and operated only by trained personnel.
5.5 A portable carbon dioxide fire extinguisher shall be conveniently located in the test area for emergency use.
6. Sampling
6.1 Take all fluid samples in accordance with Practice D4057.
6.2 Clean, dry, and free all sampling apparatus from any substance that might contaminate the fluid.
6.3 Care shall be taken to ensure that the fluid is mixed properly before samples are withdrawn for test and that the samples are representative of the whole.
6.4 The fluid shall normally meet the specification requirements at the point where it passes from the supplier to the consumer unless other contractual arrangements have been made.
