Gas detection: A guiding hand

There are many varieties of gas detection monitors and systems on the market affording high levels of protection.

Knowing which product is suitable for a particular application can be confusing, as Scott Safety explains

The issue of air quality is one that workers in many industries around the world have to face on a day-to-day basis. The air that we breathe is made up of a number of different gases and if the balance of these gases is altered, or an additional, harmful gas introduced, our safety can be compromised. In 2009/10 there were seven fatal injuries and 162 over-3-day injuries* as a result of poisoning and/or exposure to harmful gases, indicating that although there are many forms of gas detection products and respiratory protective equipment (RPE) available, there are still a worrying number of deaths and injuries to workers in hazardous environments.

Know your gases Hazardous gas monitoring is a danger that many different industries face, including petrochemical, oil and gas, pharmaceutical, and wastewater treatment facilities. Knowing the dangers, Scott Safety has produced a detailed Gas Detection Reference Guide to help others understand and identify the properties and hazards of the gases that can enter the workspace and how best to protect themselves. The guide includes information on the different types of technology used in gas detection, the benefits and limitations of the different sensor types and how they can be best used to provide the safest protection.

It breaks each industry down into the potential activities that would require the need for gas detection and the notable gases that could be present. Understanding the different types of gases and the dangers that they can pose is the first step in choosing the correct form of gas detection. The guide lists the different gases that could be present within a workplace and the effect they can have, such as suffocation, cancer or causing explosions.

Even the most common gases, such as oxygen and nitrogen can have devastating effects if present in dangerous levels.

Each gas has certain exposure limits (the concentration to which workers can be exposed continuously for a short period of time), which are broken down into; permissible exposure limit, short term exposure limit and threshold limit value. The combustible gas reference table and toxic gas reference table within the guide, set out the different gases, their various limits, and the lowest airborne concentration that can be detected by smell along with a 'how to' section verifying how to use the tables.

Fixed versus portable detection The most common application in hazardous atmosphere monitoring is the use of mounted, fixed gas detection systems. These are set up to provide continuous monitoring in areas where leaks, ruptures or releases of hazardous gases are likely to occur.

Designing a gas detection system, that meets requirements and protects the workers, comprises of a number of components and can be tailored to differing needs.When designing a fixed gas detection system the following areas need to be considered: Understand the application Identify the potential danger points Establish the response functions Determine gas characteristic Profile the facility Portable gas detection is a handheld or body mounted system of sensors that provide protection to an individual user, with the use of visual, audible and vibratory alarms. Portable gas detectors can usually be configured in different sensor combinations for use in multiple applications including confined space entry, where fixed gas detectors are not available or to verify that an atmosphere is not hazardous when servicing a fixed gas detection system.

Gas detection standards As with many products that are made to protect people, the standards and approvals for gas detection are numerous and can be confusing. It is important to understand the many markings that can appear on the products and their significance and value.

Within the Guide, Scott Safety has dedicated a section to each different standard or approval to clearly define what they mean and how they should be applied to the different gas detection products, including: Hazardous area classifications Protection methods and standards NEMA classifications/Ingress protection CE Marking Scott Safety is offering its guide free on its website. If you would like a copy, please visit www.scottsafety.com/gasdetectionguide.

* www.hse.gov.uk/statistics/tables/index.htm - Table RIDNAT - 2009/10p