Molecular weight
The sum of the atomic weights of all the atoms in the molecule (the weight of one molecule of the chemical).
Immediately Dangerous to Life or Health
The Immediately Dangerous to Life or Health level is a limit originally established for selecting respirators for use in workplaces by the National Institute for Occupational Safety and Health. A chemical’s IDLH is an estimate of the maximum concentration in the air to which a healthy worker could be exposed without suffering permanent or escape-impairing …
Level of Concern
A threshold value of a hazard (toxicity, flammability, thermal radiation, or overpressure); the LOC is usually the value above which a threat to people or property may exist. For each LOC you choose, ALOHA estimates a threat zone where the hazard is predicted to exceed that LOC at some time after a release begins.
Detonation explosion
An explosion where the flame front travels at supersonic speeds as a shock wave. Explosions of this nature are often triggered by a high-power explosive device. Typically, detonation explosions are significantly more damaging than deflagration explosions.
Combustible liquids
Term used by NFPA and DOT to classify certain liquids that will burn, on the basis of flash points. NFPA and DOT generally define “combustible liquids” as having a flash point of 37.8°c or higher. They do not ignite as easily as flammable liquids; however, they can be ignited under certain conditions, and must be …
Ceiling Limit; Threshold Limit Value – Ceiling
The maximum allowable human exposure limit for an airborne substance which is not to be exceeded even momentarily.
Air exchange rate
The number of times per unit time that the volume of air within a building is completely replaced by new outdoor air when doors and windows are closed. Usually expressed as number of air changes per hour
Hydrates
Hydrates are a physical combination of water and other small molecules that form a solid material with an ice-like appearance but significantly different in structure and properties than ice. The hydrate inhibition solution must ensure that hydrates do not form
Two phase flow
The combined flow of oil and gas in a pipeline presents many design and operational difficulties not present in single phase liquid or vapour flow. Frictional pressure drops are harder to estimate. Liquid is likely to gather at low points in the pipeline and reduce the pipeline capacity to a point when slugs of liquid …
Non Return Valve
Chicksan valve that only allows flow in one direction