By Don Galman, Honeywell
There are many gas detection products on the market that might appear to be the same, but a closer inspection of specification, functionality and features reveals major differences in what products can do and the potential value they can offer. Similarly, individual applications are also unique in their respective designs, needs and processes undertaken.
Know your site risks
Before beginning to consider gas detection equipment, a risk assessment needs to be conducted. Any company employing staff has the obligation to conduct risk assessments to identify potential hazards and these can include potential gas, vapor or Oxygen deficiency risks. If gas hazards are identified, gas detection is applicable as a risk reduction method.
Identifying the prime objective
Depending on the processes being undertaken and the gases being detected, remote or off-site alarm notification plus event data logging/reporting may also be required for Health and Safety management records. Another factor impacting on the need for enhanced reporting functions might be regulatory compliance or a condition of insurance.
Ask the right questions
Having identified the primary objective, the suitable equipment is selected by asking a number of key questions. These fall into three broad categories:
- The gases to be detected and where they may come from
- The location and environmental conditions where detection is to take place
- The ease of use for operators and routine servicing personnel
Identify the gases to be detected and where they may come from
The gases to be detected should be identified by the risk assessment, however experienced gas detection equipment manufacturers and their approved distributors are often able to help in this process, based on their experience of similar applications. However, it is important to remember that it is the end-user’s responsibility to identify all potential hazards.
It is also essential to identify the potential source of a gas release as this helps determine the number and location of detectors required for a fixed gas detection system.
Consider the environmental conditions
The performance, accuracy and reliability of any gas detection equipment will be affected by the environmental conditions it is subjected to. Temperature, humidity and pressure levels at the location all have a direct bearing on the type of equipment that should be selected. Additional factors such as potential variations resulting from a production process itself, diurnal/nocturnal fluctuations and seasonal changes may also affect the type of device which is suitable.
Understand product functionality
The next area of consideration relates to additional product functionality. Aspects like wiring configuration are important, especially when retro-fitting into an existing application. If the apparatus is being integrated into a separate safety system, certain communication protocols may also be required such as HART®, Lonworks or Modbus®.
Consideration will also need to be given regarding the requirement for local displays on transmitter units and local configuration of the unit and gas displays may also be a useful addition.
Measure the ease of use for operators and routine servicing personnel
Routine maintenance is another important consideration. Some gases and vapors can be detected with a number of different sensing technologies, e.g. Hydrocarbon gases with catalytic beads or Non-dispersive Infrared NDIR. Catalytic beads do not provide fail-to-safety operation and therefore can require a high frequency of routine maintenance, however NDIR based solutions tend to have a higher initial purchase price, but may require less routine maintenance. In-house resource to undertake such routine maintenance needs to be identified and in the absence of such a resource, budgeting for third party maintenance is an important factor in selecting the right equipment.