Which practice is recommended for LEL reading during a suspected gas leak?

For identifying the Lower Explosive Limit (LEL) during a suspected gas leak, measuring high in the middle of the room is important because many gases, especially lighter than air gases like natural gas, rise and tend to accumulate at higher elevations. Consequently, measuring at a higher level provides a more accurate assessment of the concentration of gases in the area. This practice helps in determining whether the gas concentration poses an explosive risk.

When considering other options, measuring low near the floor is less effective for lighter-than-air gases. Conversely, measuring outside the building might not provide relevant information about the gas concentration indoors. Also, measuring at any height without specific regard to the behavior of the gas can lead to inaccurate readings, as gas dispersal is affected by factors such as ventilation and wind. Overall, taking measurements in the middle of the room at a height where gas is likely to accumulate ensures a more thorough and reliable assessment of the situation.