Gas Detectors Explain 'Detection Ranges'

The experienced and capable team at Gas Detectors have a few words of advice to those contemplating buying a gas detector, and explain the differences between pumped models and the rest. As they say, a common myth in the portable gas detection industry is the concept of a “detection range” — the area around a gas detector that is monitored for hazardous gases. Believing in detection ranges may lead workers to ask questions such as will the instrument detect a hazardous gas at five feet or 25 feet away, how much will the detection range increase by adding a pump and do they need more than one gas detector if their whole team is working in the same room.

These questions come from the belief that gas detectors “search” for gases and detect them from afar. Unfortunately, this isn’t true. For traditional portable gas detectors, the answer is easy – the only gases detected are the ones immediately in front of the instrument that diffuse into the sensors. Gas detectors are not capable of alerting users of hazards that are 10 feet away, or even 10inches away. This fact leads users (and some uninformed salespeople) to recommend using a pump for personal protection applications, not simply for traditional pumped applications like confined space entries. The fault here is that a typical instrument’s flow rate is between 250-500ml per minute. A typical adult male inhales approximately 30 litres per minute while walking – a volume that is 60-120 times greater. In other words, the flow rate of a pump is minuscule compared to a person breathing.

In order to be most effective, an instrument should be worn in the user’s breathing zone. OSHA defines a breathing zone as “a hemisphere forward of the shoulders within a radius of approximately six to nine inches.” A small pump in the gas detector placed next to a person breathing has little impact on the environment. As a result, a pump offers minimal value for personal protection applications.

For those looking to purchase a gas detector for personal protection, they should think carefully before choosing a pumped instrument. Unless the instrument will be used for multiple applications (e.g. personal protection and confined space entries) the pumped instrument may cause stress in the future for a few reasons, such as they are typically more expensive and they often fail when water, dust or debris is sucked into the inlet, leading to increased repair costs and downtime.

For more information on Gas Detectors and their products and services, please visit the website at http://www.gasdetectors.co.nz .