CONFUSION OVER TERMINOLOGY, DEVELOPING CONSENSUS
Asked if he thinks the current definition of an FRF is clear, David Phillips, hydraulic fluid and lubricant consultant with W. David Phillips & Associates, says, “No, there is still a dichotomy between the requirements of ISO and those of Factory Mutual Corp. ISO has recently published a revised specification for fire-resistant hydraulic fluids, and attempts will be made to obtain precision data on the different ISO fire-resistance methods. If this is successful, it may then be possible to classify fire resistance on the basis of performance in the different tests.”
Coming to consensus definitions of fire-related properties is of utmost importance because the consequences, in terms of injury and death, legal proceedings and financial losses, are so high. The meaning of fire resistant varies from discipline to discipline, industry to industry and material to material. Both fire resistant and fireproof are (wrongly) used as synonyms for incombustible and not ignitable. Actually combustion and ignition can create a fire independently of each other. For example, water-based lubricants can ignite without combusting. When the temperature is sufficiently high, a fluid can combust but not ignite. Fireproof should refer to a substance that is neither ignitable nor combustible. Fire resistant should refer to the degree of resistance to ignitability and combustibility. It’s important to note that the terms flame-propagating and combustible are not synonymous. Following are some very basic consensus definitions:
FIREPROOF: Impossible to ignite, combust or propagate a flame.
FIRE RESISTANT: Extremely difficult or impossible to ignite and not capable of propagating flame.
FIRE RETARDANT: Difficult to ignite and will not significantly propagate flame.
IGNITABLE: Energy from an ignition source can raise the temperature to point of ignition.
COMBUSTIBLE: Burning (combustion) results in a flame.
FLAME PROPAGATING: Roughly the same as combustion (but there must have been an original ignition). Fluid continues to burn (as a flame) when it is no longer in contact with the ignition source.
Sidebar 1 from Fire-Resistant Fluids Cover Story from July 2013 TLT