Arenas use a variety of gases for the general operation and maintenance of the facility, including the refrigerant (ammonia or CFC/Freon) and often propane. These gases are safe when used properly and with well maintained equipment, but there is always a possibility of equipment problems or operator error that can cause leaks on occasion. Also, many rinks have air quality problems attributed to excessive levels of gases such as carbon monoxide.
Who needs a gas leak detector?
The CSA B52 Mechanical Refrigeration Code in Canada, and the ANSI/ASHRAE 15 Safety Code for Mechanical Refrigeration in the USA, has specific requirements for refrigerant leak direction systems. In general, systems over 100 HP, or any system required to be housed in a standard or Class T machinery, will by code require a detector.
Regardless of specific codes, the escalating costs of refrigerant, as well as concerns for safety and the environment, have led to the use of detection systems even in the smallest systems. In addition, more stringent ventilation code requirements, especially in ice rinks, has led to the increased need for both carbon monoxide (CO) and carbon dioxide (CO2) monitoring.
How to leak detectors work?
There are five types of sensors available for leak directors which range dramatically in price and features. Chemical (detector tubes) are the lease expensive then solid state, electrochemical, infrared, and ionmobility spectrometers as the most expensive. Each of these have various pros and cons;
Solid State sensors use a heated semiconductor that changes internal resistance when in contract with the refrigerant, and can direct in a rang of 50 to 100 PPM (50 to 95F/50 to 80% humidity). These sensors are not only economical, but are very reliable and have a long life expectancy. The disadvantages include sensitivity to other gases, sensitivity to moisture and temperature changes, and that special care is required in the placement.
Electrochemical sensors use electrodes immersed in an electrolyte under a permeable membrane, and measure change in potential when gas permeates the membrane. These are very selective to the refrigerant and can measure levels from 0.7 to 100 PPM (-40 to 95f; 20 to 90%RH), but have a short life expectancy can "go to sleep" without warning, and have a high replacement cost.
Infrared sensors project infrared light through a gas sample, and measure the amount of light and wavelength of light absorbed. These are very specific to refrigerant and are very minimally affected by humidity and temperature, measuring from 0 to 1000 PPM (10 to 95F; 0 to 90% humidity). This would be an ideal sensor to use, but they are very expensive and require more frequent calibration.
What features should you look for in a gas detector?
The low cost and proven reliability of solid state sensors has made them the most popular method of leak direction available for ice rinks.
When purchasing a gas detector for your facility, be sure to do your homework and make sure it will suit your specific requirements.