Tag Archive | "chlorine"

Four Channel Gas Detector for Wastewater Treatment Plants

Critical Environment Technologies Canada Inc, (CETCI) offers strategic and reliable gas detection solutions for many applications, including wastewater treatment plants. Our QCC Quad Channel Controller, is an ideal fixed gas detection system for this type of application.

A wastewater treatment facility is a wet maze of rooms, pipes, pumps, wells, chambers, concrete tanks and settling basins. Each treatment stage the wastewater goes through involves hazardous gases that may be already present, are produced or are added to complete the process. To ensure the safety of the workers, equipment and the facility, every area presenting a gas hazard should be monitored, including the gas storage rooms, ozone generator room and any room that gas passes through. In the larger, open areas, a fixed gas detection system is suitable; in confined spaces that operators enter and where gas may be present, portable gas detectors are more appropriate.

The most common hazardous gases found in this type of facility are hydrogen sulphide, methane, ammonia, carbon monoxide, chlorine and oxygen deficiency. Some facilities may also use ozone, chlorine dioxide or sodium hypochlorite with the chlorine during the sanitization treatment process. Furthermore, sulphur dioxide is often used to de-chlorinate the water once the treatment process is complete.

CETCI’s QCC Quad Channel Controller offers a fixed, continuous gas monitoring solution with four gas channels, three programmable relays, a door mounted audible alarm and an optional BACnet RS-485 output signal for communicating with a building automation system. The four gas channels can be configured with any combination of analog or digital transmitters with the same or different types of gas sensors. For large applications, multiple QCC controllers can be networked together, each providing another four available gas channels and 3 relays. Other value added, optional features include 2 analog outputs with a data logger, manual equipment ON/OFF switch, top mounted strobe, remote strobe and horn combo and a remote display module that offers the ability to view the gas level readings in a separate location from the controller and transmitters.

The potential for physical damage to the gas detection equipment is high in this type of harsh, wet environment. CETCI’s equipment is constructed to withstand the unpredictable water levels and acidic or caustic conditions from gases like hydrogen sulphide and chlorine when it mixes with water.


About Critical Environment Technologies Canada Inc.

Critical Environment Technologies designs and manufacturers indoor air quality and fixed gas detection systems including self-contained systems, controllers and transmitters (analog, digital and wireless). Applications include commercial HVAC, institutional, municipal and light industrial markets worldwide. Many of these applications are for vehicle exhaust, but areas of specialization include refrigeration, food processing plants, manufacturing plants, wastewater treatment plants, commercial swimming pools and many more.

For more information about our products, check out our website at www.critical-environment.com or to discuss a tailored gas detection solution for your application, contact us at 1-877-940-8741.

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Where are the Gas Detectors in Public Swimming Pool Facilities?

Indoor swimming pools provide exercise and recreational fun for all ages. To ensure swimmers are submerged in crystal clear, sanitary water, a disinfectant maintenance program using Chlorine, or Chlorine & Ozone are commonly followed to treat the pool water. Chlorine is a powerful, corrosive disinfectant and in both gas and liquid forms it is toxic and hazardous to living beings at concentrations as low as 1 ppm. Ozone is created by exposing oxygen to a high voltage or ultraviolet radiation. It is more powerful than Chlorine and when used in conjunction with Chlorine it helps provide an odourless, clear water environment. Less Chlorine is required when Ozone is used as part of a swimming pool sanitization program.

The areas for potential gas leaks of Chlorine and Ozone are found around the equipment in the Chlorine Feed Room and the Ozone Generator Room. In a typical swimming pool application where only Chlorine is being used to disinfect the pool water, we suggest a controller or transmitter with  a display, audible alarm and relay outputs, be mounted outside the Chlorine Feed Room beside the inspection window so it can provide a visual confirmation of the gas level readings prior to entry. If there is a Chlorine leak, the controller or transmitter will alarm and trigger the relays to shut down the ventilation system until it is safe to exhaust the gas from the contaminated area, or activate the ventilation system depending on the local regulation codes. Inside the Chlorine feed room should be mounted a remote transmitter with a Chlorine sensor that provides continues monitoring for leaks and communicates with the controller outside the room. Chlorine is heavier than air and tends to collect in low-lying areas, so the gas detector inside the room should be mounted 6 inches above the floor, close to the area of a potential leak, but away from the ventilation fans and any pockets of air currents.

Similarly, in a typical swimming pool application that uses Chlorine & Ozone to disinfect the pool water, in addition to the aforementioned gas detection system for Chlorine, we suggest a similar set-up for the Ozone Generator Room. A controller with a display, audible alarm and relay outputs should be mounted outside the room to provide confirmation of the gas levels inside the room prior to entry. A remote transmitter with an Ozone sensor should be mounted inside the generator room, near the equipment and between the generator and the destructor. Pure Ozone is slightly heavier than air but does not necessarily settle to the floor. If additional reaction tanks or destructors are more than 16 ft (5 m) away from the existing sensor, an additional sensor may be required. If there is an Ozone leak, the controller will alarm and trigger relays to activate the emergency air exhaust system.

For both applications a remote visual alarm device such as a strobe should be mounted on the ceiling or wall inside the pool area to provide an additional visual alert in the event of a leak inside either room.


View Diagram


There are outside influences that affect the operation of gas detectors and the equipment with which they interface. In addition, sensors change characteristics as they age; they have a set lifespan and deteriorate over time. Regular maintenance of the gas detection system by a qualified technician is as important as a proper installation. For a newly installed system or as part of a very thorough maintenance schedule it is recommended that a bump test be done every 30 days. A bump test basically follows the same procedure as a calibration, but it normally uses less gas and requires less understanding of the intricate workings of the gas detector. A bump test tells you if the detector is malfunctioning or operating normally, if the sensors are responding to the gas as they should and if the low, mid and high alarms are being triggered. This level of upkeep allows you to determine that the daily readings are accurate and the devices are working correctly. If the system malfunctions or goes into fault, patrons and workers would be unprotected if a leak was to occur during that time.

If a bump test fails, a full calibration is required. Calibration is more time consuming than a bump test and should be done by a qualified technician. It is recommend that a full calibration be done every 6 months, regardless of the performance or type of gas detection device. Calibration is like resetting the parameters of the device, in terms of telling what it should be doing at what level. It could be compared to a reset button. As the sensors age, their sensitivity to the gas decreases. Calibration allows you to compensate for that deterioration and keep the sensor detecting the gas at the appropriate levels so that the low, mid and high alarms go off as they should.

It is important to keep a maintenance log with dates and services performed. After a full calibration, a service sticker should be place on the device indicating when the next calibration should be done.

When bump testing or calibrating a Chlorine or Ozone sensor, there are a few things to keep in mind. Both Chlorine and Ozone are considered to be one of the “sticky gases”, meaning they adhere to surfaces and as a result, decrease in concentration. During the flowing of the gas over the sensor, the gas will adhere to the inside of standard tubing and the lengthier the tubing the less gas is left to hit the sensor. Using Teflon lined tubing is recommended, as is a length of tubing no longer than 2 to 3 feet so the gas flow concentration doesn’t lessen over the distance from the gas cylinder to the sensor.

Last but not least, when calibrating a Chlorine sensor, to ensure you get true readings, it is recommended that you use a Chlorine gas generator rather than a cylinder of Chlorine gas. The stability and quality of the chlorine gas is much higher from a generator, making calibration easier and accurate.

For suggestions on gas detection systems, indoor air quality monitors and calibration, please visit www.critical-environment.com


Written by Rebecca Erickson

Ozone Safe Work Practices, 2006 ed. WorkSafe BC 
Chlorine Safe Work Practices, 2002 ed. WorkSafe BC

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Chlorine Gas

Chlorine is the most used for industrial products around the world. This element is abundant in the earth’s crust and oceans. It is used to manufacture plastics, synthesize other chemicals, purify water supplies, treat sewage, and make refrigerants, varnishes, pesticides, drugs, disinfectants, and bleaches.

Chlorine is compressed gas that is very toxic, corrosive and a strong oxidizer. Extreme caution and safety equipment should be used when around any form of chlorine. When a person breathes chlorine, the corrosive substance splits hydrogen from water in most human tissue, releasing oxygen and hydrogen chloride, which can cause severe burns. Scientists say there are palliative remedies but no antidote.

Chlorine gas cylinders were first used by the Germans in 1915 as a chemical weapon. Chlorine gas destroyed the respiratory organs of its victims and this led to a slow death by asphyxiation. Chlorine is a severe eye, skin, nose, throat and upper repertory tract irritant. Small exposure causes coughing; choking, wheezing and burning of the eyes, throat and skin which can cause frostbite. Large exposure causes the airways to constrict, at the same time fluid builds up in the lungs causing the victim to drown. High doses can kill within a couple of breaths.



“Capital is Coming to Kill You with Chlorine This Time”. Infoshop News. 20 Oct 2011. Web. 20 Jan 2012. <http://news.infoshop.org/article.php?story=20111020162216998&query=capital+is+coming+to+kill+you>.

“OSH Answers: Chlorine”. Canadian Centre for Occupational Health and Safety. 19 Feb 1999. Web. 20 Jan 2012. <http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/chlorine/basic_chlorine.html>.

“Chlorine”. Wikipedia. 7 Nov 2012. Web. 20 Jan 2012. <http://en.wikipedia.org/wiki/Chlorine>.

“Chlorine Gas”. Spartacus Educational. Web. 7 Nov 2012. <http://www.spartacus.schoolnet.co.uk/FWWchlorine.htm>.

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Importance of Air & Water Testing in Indoor Pools

Have you ever wondered why your eyes hurt or why you have a cough after swimming at an indoor pool? We all assume that it’s from too much chlorine in the pool but that is false!

If the pool staff doesn’t regularly test and monitor both the air and water indoors, the environment becomes very toxic and unsafe to everyone in the building. Water is an essential ingredient for all life as we know it, and unfortunately that means that many different organisms thrive in untreated pool water.

Untreated pool water rapidly deteriorates and cause many irritants to all users and employees; such as stinging eyes, nasal irritation, coughing, wheezing, e-coli, guardia, and asthma. These toxins (by products) are created when chlorine binds with sweat, urine and other wastes from swimmers. As the concentration increases in the water, these toxins then move into the surrounding air. Without enough fresh air flow over the water, the pool & air will become saturated with these toxins.

If you or your child plans on using an indoor pool, it’s a very good idea to shower with soap before you enter the water and after. With children you should check often if they need to use the bathroom and never change your child’s diaper on the pool side.

The most common disinfectant used in pools is Chlorine and is available as a pure gas, mixed in a granular powder or liquid form. Chlorine is an odorless gas but the chloramines’ compounds resulting from its interaction with ammonia or organic contaminants have the strong odor typically associated with chlorinated pools.

This is why it’s so important to test the air & water at indoor pools. Some indoor pools will use special UV ultra violet light or ozone for treatments in addition to chlorine disinfection to improve air & water quality. Most pools will monitor all levels for any chemical used to treat & maintain toxins to ensure the health and safety for all users and employees. Most indoor pools will have a ventilation system in place; the key is to make sure there is lots of fresh air flow into the pool areas. In order to monitor the ventilation, pools will install fixed gas detectors to monitor ammonia, chlorine and / or ozone depending what is used as a treatment.

For suggestions on fixed gas detectors, please visit www.critical-environment.com.

Written by: Ambur Vilac & Teresa Kouch



Barlowe, Barrett. “What Are the Dangers of Indoor Swimming Pools?” Livestrong.com. 14 June 2011. Web. 06 March 2012. <http://www.livestrong.com/article/258007-what-are-the-dangers-of-indoor-swimming-pools/#ixzz1ekIDtD2Z>.

Barlowe, Barrett. “Swimming Pool Chemical Treatment.” Livestrong.com. 14 June 2011. Web. 06 March 2012. <http://www.livestrong.com/article/231589-swimming-pool-chemical-treatment/#ixzz1ekJgTyY6>.

“Irritants (Chloramines) & Indoor Pool Air Quality.” Centers for Disease Control and Prevention. 12 April 2010. Web. 06 March 2012. <http://www.cdc.gov/healthywater/swimming/pools/irritants-indoor-pool-air-quality.html>.

“Leak Detection on Indoor Swimming Pool in Essex.” Professional Swimming Pools. 20 January 2012. Web. 06 March 2012. <http://www.professionalswimmingpools.com/2012/01/leak-detection-on-indoor-swimming-pool-in-essex>.

“The Hazards of Swimming Pool Chemicals.” Professional Swimming Pools. 2010. Web. 06 March 2012. <http://www.professionalswimmingpools.com/psp-services/members-area/pool-chemicals/the-hazards-of-swimming-pool-chemicals>.

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The Wonders of Ammonia & Chlorine

They Are All Around You: Ammonia & Chlorine. Be Aware of Them and Stay Safe.

The two most common chemicals found in your home, office and commercial facilities in one form or another are Ammonia (NH3) and Chlorine (Cl2). They are also two of the oldest and most widely produced chemicals in commercial use around the world.

Ammonia, a refrigerant by “nature”
Refrigeration by mechanical means goes back to the 1800s and ammonia was among the earliest chemicals to be compressed for this purpose. Commercial use of ammonia, as a refrigerant, was fairly common by the late 1800s. Ammonia was first synthesized in 1823 and the first commercial production of synthetic ammonia began in 1913.

Ammonia refrigeration was being used in ice rinks as early as the 1920s. Commercial use of ammonia as a refrigerant is virtually all around us. It can be found in ice systems for ice arenas, commercial coolers and freezers, refrigeration systems, college campuses, office parks, air conditioning for the International Space Station and Biosphere II, commercial fertilizers, etc.

Ammonia is low cost, non-ozone depleting and does not add to global warming. It is abundant and the most energy efficient gas used as a refrigerant and is manufactured using natural elements of nitrogen and hydrogen. It is unlikely it will be phased out because of this but it is none the less a very dangerous gas if not handled properly. It is a colorless gas with a pungent, choking odor and is lighter than air; thus it typically rises to the highest area in a room when it escapes. It is water soluble; therefore, makes it useful as an additive to many cleaning products. It is a safe gas when handled correctly but can be detected by the human nose at very low concentrations of ≤ 50 ppm and will not ignite in air. It has a very irritating affect on the airways to the lungs and eyes and should not be inhaled.

Chlorine, a sanitizer by “man”
Chlorine is a sanitizing gas. When mixed with water, it produces two chemicals that kill microorganisms by oxidizing them. Chlorine was discovered in 1774 by a Swedish chemist. For the most part, Chlorine is manufactured by passing electricity through salt water. When proper concentration is mixed with water, it acts as a common sanitizer for commercial and home pools and spas killing microorganisms. Pool water with properly mixed and monitored (daily), chlorine is quite safe and has about the same chlorine levels as tap water. Regardless, use extreme caution when handling chlorine in any form. Avoid breathing chlorine fumes directly as they can have a burning (oxidizing) affect on the lungs.

Never mix chlorine with any other chemicals as this could be extremely hazardous. In other words, it can become toxic and even explosive. Some people have skin allergies and red eye to chlorine and chloramines found in pool water that is not balanced properly. Chloramines are produced when chlorine in pool water mixes with perspiration, oils and urine from swimmers’ bodies. Hypochlorous acid, one of the two chemicals formed from mixing chlorine and water, reacts with ammonia which is a component of sweat and urine producing chloramines. Improperly balanced chlorine levels in pool water could result in very high levels of chlorine, releasing gas from the surface of the water potentially causing breathing difficulties for some people. Anyone handling the chlorine concentrations used in commercial pools should be properly trained and always wear protective gear for hands and eyes.

Gas detectors, a commercial requirement
In commercial areas, gas detectors are required and used to detect leaking ammonia or chlorine. Every commercial arena has ammonia sensors and every commercial pool has chlorine sensors for worker and patron safety. These sensors will detect the smallest leaks and send a signal to controllers that alarm when levels climb above preset values established by Occupational Safety and Health Organization in all provinces and states for workplace exposure to toxic gases. The gas detectors typically activate or halt ventilation equipment(s), depending on the application, and alarm to warn workers of a small leak. The activated warning alarms let workers know to evacuate all patrons and call the local fire department if the leak increases to higher concentrations. Because they are both very hazardous gases at very low levels, these sensors should be gas calibrated for accuracy every six months and bump tested every month for safety purposes.

Enjoy these wonderful public facilities but be aware of your surroundings for your health and safety.

Written by: Frank Britton, CETCI’s General Manager

REFERENCES: www.eHow.com, www.amonia21.com, www.mama’shealth.com

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Gas Detectors

CETCI gas detectors are used to detect many different gases. Some of the most common are Carbon Monoxide, Carbon Dioxide, Nitrogen Dioxide, Nitric Oxide, Ammonia, Chlorine, Ozone, Combustible Gases like Methane and Propane, Oxygen, Refrigerants and more.

IAQ Monitors

The YES Series of IAQ Monitors are essential for those responsible for conducting Indoor Air Quality (IAQ) Investigations. These instruments are specifically designed to measure and record the quality of indoor air in offices, buildings, homes, schools, parking garages, ice rinks, etc.