Glossary of Terms: E

Electrochemical sensor
A gas sensitive electrode, formed by a permeable membrane and special electrolyte.
EMC
Electromagnetic compatibility.
Engineering controls
reduction of worker exposure to airborne contaminants by modifying the source or reducing the quantity of contaminants released to the workplace
Environment
The surrounding conditions, influences, and forces to which an employee is exposed in the workplace.
EPA
US Environmental Protection Agency.
Epidemiology
The science that deals with the study of disease in a general population. The rate of occurrence and distribution of a particular disease (by age, gender or occupation) may provide information about the causes of disease.
Ergonomics
An applied science that studies the interaction between people and the work environment. It focuses on matching the job to the worker.
ESD
Electrostatic discharge.
Evaporation rate
The ratio of the time required to evaporate a measured volume of a liquid to the time required to evaporate the same volume of a reference liquid (butyl acetate, ethyl ether) under ideal test conditions. The higher the ratio, the slower the evaporation rate. The evaporation rate can be useful in evaluating the health and fire hazards of a material.
Evaporation
The process by which a liquid is changed into the vapor state and mixed with the surrounding air.
Ex d Flameproof
any flame is contained within the housing of the product. Suitable for zones 1 & 2.
Ex e Increased safety
No sparks or hot surfaces. Zones 1 & 2.
Ex ia Intrinsic safety
the internal power of the device is so low that it cannot cause an ignition, even with one fault (Ex ia) or two faults (Ex ib).
Ex m
Encapsulated to keep gas out of product. Zones 1 & 2.
Exceedance Level (Ln)
Percent of the run time that was spent at or above the corresponding dB level. Example: An L40 equal to 73dB would mean that for 40% of the run time, the decibel level was equal to or higher than 73dB.
Exchange Rate (ER)
Refers to how sound energy is averaged over time. Using the decibel scale, every time the sound energy doubles, the measured level increases by 3dB. This is the 3dB exchange rate that most of the world uses. For every increase of 3dB in the time weighted average, the measured DOSE would double. Some organizations such as OSHA in the U.S. have argued that the human ear self-compensates for changing noise levels and they felt that the 3dB exchange rate should be changed to more closely match the response of the human ear. OSHA currently uses a 5dB exchange rate, which would mean that the reported DOSE would double with every 5dB increase in the time weighted average. The exchange rate affects the integrated reading LAVG, DOSE, and TWA but does not affect the instantaneous sound level.
ExpHrs
Hours of sound exposure. Accumulated exposure to sound measured in hours using an Exchange Rate of 3 dB. The display will switch to ExpSec if RTIME is less than one hour.
Explosion proof
A name for Ex d apparatus design.
Exposure records
The records kept by an employer, or company doctor or nurse of an employee’s exposure to a hazardous material or physical agent in the workplace. These records show the time, level and length of exposure for each substance or agent involved.
ExpSec
Seconds of sound exposure. Accumulated exposure to sound measured in seconds using an Exchange Rate of 3 dB. The display will switch to ExpHrs if RTIME is greater than 3600 seconds.