Ionization and Photoelectric Smoke Detection

It turns out, smoke detector does not necessarily equal smoke detector. As with any technology, the detection of smoke has evolved. The two most-used technologies are ionization and photoelectric. While both technologies sense the presence of smoke, the technologies are quite different. Smoke alarms for home, as well as smoke detectors for fire alarm systems employ these technologies. In this post we will explore the major differences between the two.

Smoke detection history

Smoke Alarm on Yellow Background

Many separate inventions ended up forming what we know as a smoke detector today. Fire alarms and smoke detectors used to be reserved for large commercial and industrial facilities, due to their cost and also size. The first affordable smoke detector with a battery was brought to market by the 1960’s. This detector was an ionization type detector. The technologies further advanced and allowed for the cost of the detectors to drop significantly to the levels we know today. The photoelectric smoke detector was invented in 1972, further advancing the smoke detector.


As the first invention for fire detection after the heat detector, Ionization minimized the time it required to sense a fire. Ionization uses a tiny amount of radioactive material, which ionizes the air. That is where the technology gets its name. The material used is generally Americium-241. The unit consists of two chambers. One chambers is free to the air and the other is a closed chamber. Both are exposed to the ionization and have two electrodes. the resulting current from the ionization between the electrodes is the same, until smoke enters the open chamber. It interrupts the flow of the current in the chamber and will cause an alarm condition.


Photoelectric detectors also have a chamber and look for obscuration of the air. That is where the similarities end. This technology employs a a source of light, usually emitted by a small LED and a receiver. This light beam is constant across the chamber. Should smoke enter the chamber, the light beam is interrupted and cannot be seen by the receiver anymore. It then causes an alarm condition within the detector. Photoelectric sensors are generally said to be more effective for smoldering fires, while ionization detectors shine for flaming fires.

What detector should you get?

Photoelectric detectors, being the most popular type detectors do provide adequate response to all types of fires. A recommendation is to purchase a detector that is multi-technology, such as a combination heat/smoke detector or a detector that combines the photoelectric and ionization technologies. While there is nothing wrong with a photoelectric only detector, it increases occupant safety to take it a step further. On that note, the ionization detector, while it contains radioactive material, uses Alpha radiation to ionize the air. This type of radiation has a very low penetration, which means it is stopped by the plastic around the detector and does not present a hazard.

CO Detectors

While on the topic, I would like to touch on carbon monoxide detectors, as they are closely related to smoke alarms. Many smoke alarms come as a combination unit with CO detection. CO detectors are a small chemistry lab. The presence of carbon monoxide causes a chemical reaction with an electrolyte and causes it to conduct electricity. This is an electrochemcial type CO detector. These detectors are highly effective, as they have a 5 to 10 year lifespan and are highly reactive to exact concentrations of carbon monoxide gas.

Detector Lifespan

Most smoke alarms and combination units have an expiry date printed on them. If your unit does not have an expiration date, we highly recommend it be replaced as soon as possible. Smoke alarms become less sensitive over their lifespan and collect dust, insects and other contaminants that can affect the effectiveness of the unit. Smoke alarms usually have a 10-year life, though that may differ for combination units. Most The detectors have a mechanism built in that will chirp the detector when its lifespan has been reached.


With Ionization smoke alarms containing radioactive materials, it is a good idea to return the unit to the manufacturer upon its expiration. While the radioactive material is generally not harmful and also considered safe to be disposed of in household waste, it’s a good idea to minimize the potential environmental impact. The manufacturer generally takes the detectors back for their internal recycling programs. Disposal information is usually printed on the back of the unit.

Our Services

We carry a large stock of smoke alarms and combination units. Our team can assist with replacement and the regular inspection of smoke alarms and detectors of all technologies. From new installations to replacement after 10 years, our units are a match for every application and will save lives in the event of a fire emergency.

The Fire Tretrahedron

Firefighter fighting fire

The Fire tetrahedron explains the basic elements that are required to have a combustion. A tetrahedron – sorry for the geometry lesson – is a triangle with four triangular sides. Think of a pyramid with a triangle as the base instead of a square. There are four basic elements required to have a fire. The tetrahedron is composed of four sides and is the further development of the fire triangle, which only shows the elements required for an ignition.

Fire Teatrahedron showing the four elements required for fire

The Elements of Fire

For fire to exist, the right conditions need to exist. These conditions are referred to as elements. These elements are oxygen, heat, fuel and the chemical chain reaction. In the tetrahedron the chemical chain reaction generally forms the bottom of the pyramid, with the other elements depicted on the sides. Most fire extinguishing systems, such as sprinklers, extinguishers and suppression systems work on the principle of removing one or more of these elements from the fire.


Without oxygen a fire cannot start, likewise, if the oxygen is removed fire cannot be supported. Technically this element should be referred to as an oxidizer, rather than just oxygen. Oxygen is the most common oxidizer, but combustion without oxygen is also possible. Fluorine is an example of another oxidizer that could support a combustion without oxygen present. Oxygen then really is an oversimplification, but for the purpose for the tetrahedron, more than sufficient. Oxygen is a supporter of combustion and seeing that 21% of the atmosphere are oxygen, it can be easy to see why it is the most common.

Upper Explosive Limits

An example of how necessary Oxygen is to a fire would be a room that is oversaturated with a flammable gas. If there is a gas leak, the room can get filled with the flammable gas and displace all oxygen from the room. That would mean that you could theoretically create a spark and nothing would happen, as there is no oxygen present to support the combustion. That level of saturation would be referred to being above the UEL (Upper Explosive Limit) of the flammable gas in question.


For an ignition, a fuel needs to be present. Fuel can take many shapes and does not refer to gasoline specifically. Fuel could be a solid, such as wood, a liquid, such as grease, a gas, such as propane or anything in between. A sufficient amount of fuel needs to be available to sustain the combustion process.

Lower Explosive Limit

To refer back to the flammable gas example, the LEL (Lower Explosive Limit) is the minimum amount of the gas required to become a fuel for the fire. Below that limit, the gas is not available in sufficient quantity, so once again a spark could NOT light a fire. The dangers for gases specifically are within the LEL and UEL. Fuels for fire are organized by their class and assigned a letter. That is how the correct extinguishing agent can be picked for the hazard.


The term heat refers to the fuel’s flashpoint, the lowest temperature at which the fuel will ignite. There is a surprisingly small amount of heat required to start a fire. The action of lighting a match creates enough heat through friction to support the combustion process and light the match. Heat can come from many sources, such as the sun or artificially created. Many extinguishing methods work by lowering the temperature of the fuel, one major reason why water is so effective.

Chemical Chain Reaction of the Fire

The fourth element, which moves the fire from the fire triangle, the conditions needed for ignition, to the tetrahedron, the sustained combustion, is the chemical chain reaction of the fire. The chemical chain reaction provides the necessary heat to sustain the combustion. So long as this heat is provided, the fire will continue to burn and grow. It will only stop when it is deprived of one or more sides of the fire triangle.

Extinguishing a Fire

As noted above, extinguishing a fire requires starving the fuel of one or more elements of the tetrahedron. Most standard extinguishing methods work on this principle. It is important to use the correct agent for the applicable fire. We have an overview here of the different classes of fires and their corresponding extinguishing agents. Water-based sprinkler systems and other suppression systems also work along the same principles.


Safety training can be very beneficial to most organizations. A team with knowledge about how fires start and how they can be prevented can protect your facility from a disaster. Nexus Fire & Safety offers comprehensive training programs for organizations. This includes fire warden training, extinguisher training, and custom programs for specialized facilities. We are ready to assist with any questions that you may have and offer 24-hour support to keep your safety systems in top shape!

How does a Fire Sprinkler work?

Multiple fire sprinkler heads, showing their shapes and sizes

Fire sprinklers are in many commercial and even some residential buildings. Most people know that a sprinkler going off means it’s a bad day and that hanging things off them is probably not the best idea. But how do fire sprinklers work? Does that red pull station by the door turn them on, and we shut them off when the fire is out? There are many misconceptions about fire sprinkler systems. We will provide an outline of the different types of sprinkler systems and how they work. For more detail, contact us, and our team of experts can assist with any questions you may have.

Types of Fire Sprinkler Systems

While the sprinkler heads may mostly look very similar, the system behind them can be quite different. There are four main types of systems, though they all are for the same purpose of putting fires out.

Wet Pipe Systems

Single sprinkler head with sensing element visible
Visible Sensing Element

This is the most common fire sprinkler system that everyone thinks of when they hear of fire sprinklers. All pipes in the system are filled with water and each sprinkler head has a sensing element (fusible link or glass bulb). Should the temperature get too hot at the ceiling, the sensing element will burst and allow for water to flow freely. As the system is filled with water there is minimal delay from activation to system flow. Wet pipe sprinkler systems are the most reliable and cost-effective, though they may not be appropriate for every application. As the water is under pressure in the pipes, the system cannot be subjected to freezing temperatures. Additionally, water can be quite harmful, which may not be appropriate for areas with sensitive equipment.

Dry Pipe Systems

Dry pipe systems are very similar to wet pipe systems. The major difference is that the pipes are filled with air instead of water. This allows for the system to be exposed to freezing temperatures, without any impact to its functionality. Dry systems can be found on patios and canopies, coolers and parking garages, amongst other places. The system is comprised of a specialty valve that keeps the water at bay with the assistance of the air pressure in the system. The sprinkler heads still have a sensing element and upon activation the air will escape. Once enough air has escaped, the valve will open and will release the water into the system and through the sprinkler head. As there is a delay upon activation of a dry pipe system, due to the time it takes to release all the air, the size of dry pipe systems is usually limited.

Preaction Systems

Preaction systems are more specialized systems. Their basic design is quite similar to a dry pipe sprinkler system, though the activation is what differs. Preaction systems are paired with electronic detection devices. A releasing panel is paired with these heat or smoke detectors and is connected to a specialized valve. The pipes of the system are still filled with air, just as they are in the dry pipe system. The sprinkler heads also still contain a sensing element.

There are three sub-types of preaction systems, depending on their activation:
  • Non-interlock system: the system will activate on the operation of detection devices OR if the sensing element of the sprinkler head bursts
  • Single interlock system: the system will ONLY activate on the operation of detection devices
  • Double interlock system: the system will activate if the detection devices AND the sensing element of the sprinkler head bursts.

Detection devices, such as heat detectors, usually have a lower threshold for activation of 135°F (65°C) vs. 165°F (74°C) for sprinkler heads. With a preaction system, multiple criteria can be required before the system will activate. That is the reason it is ideal for museums and other sensitive environments. As the double interlock system will significantly delay activation, with both criteria having to be fulfilled, the same size limits as a dry pipe system apply. Double interlock systems were initially designed for freezer storage warehouses. Areas, where the accidental presence of water can cause a significant amount of damage, are the best candidate for a double interlock.

Deluge Systems

Deluge sprinkler head showing lack of sensing element
Deluge Sprinkler Head Without Sensing Element

Deluge systems are very similar to preaction systems. The deluge system, however, does NOT have sensing elements in the sprinkler heads. That means upon water delivery, the water will flow from ALL sprinkler heads at once. Similar to a preaction system, an electronic means of detection will keep the valve closed. Upon activation of a smoke or heat detector, the system will start flowing water and all sprinkler heads will start releasing. This type of system is most suitable for high-hazard areas, such as power plants or aircraft hangars.

So, How Does a Sprinkler Work?

As you see with the examples above, there are a few different ways a sprinkler system can work. All activations of a sprinkler system are considered automatic, as they do not require any manual input. Most sprinkler systems will activate ONLY where it is necessary, which is usually only one or two sprinkler head locations. That is the reason sprinkler systems are so effective and yet are not as destructive as everyone might think. No matter the sprinkler, the principle is the same. Upon the presence of extreme heat from a fire, the system will activate and start spraying water. Water is one of the best ways to fight the fire, as it attacks the fire in several ways on the tetrahedron. Water cools, removes the heat component, and also removes the oxygen from the fire by displacing it.

Sprinkler System Service

While this article hopefully provided you with a basic outline of sprinkler systems, there are several other components to it. Our team can assist with the design, installation, inspections, and repair of any sprinkler system. We are ready to answer any questions you may have and are ready 24 hours a day, should you encounter any issues with your sprinkler systems.

What is a Backflow Preventer

Large Dual Check Valve Backflow Assembly

When we consume water from our tap, we automatically assume that it is safe for consumn. We expect the water to be clean and free of any pollutants or toxins. Backflow preventers play a considerable part in ensuring that is the case every time. To explain what a backflow preventer is, we first need to discuss what backflow is, when it comes to water.

Water in Buildings

When water enters any building, it is pressurized by the water purveyor (usually the city or county). This pressure ensures that when you turn on the tap, the water actually starts flowing. Without pressure, the water would never flow. Because we use water for significantly more than to drink it, there are many risks of pollutants or toxins contaminating the water. Manufacturing processes or additions of chemicals (fertilizer or pool chemicals, for example) can render the water harmful for human consumption.

As buildings use water differently, there could be a time when more water is requested than can be supplied initially. A famous example for this is a fire hydrant. The hydrant, when opened will create such a high flow rate, that it pulls water back out of buildings to service its consumption. That is where the danger comes in, as the potentially contaminated water is now pulled back into the water supply and could be distributed across the entire neighborhood. This event is called a cross-connection. As the city’s water supply is cross-connected with the potentially contaminated water within the building.

One of the first-ever documented cross connections, that caused a significant amount of harm happened in Chicago at the World’s Fair in 1933. This article discusses it in more detail: Chicago Backflow Incident. Another more recent incident happened in Pittsburgh, where two fire truck pumps overwhelmed the water supply and caused fire suppression foam to leak into the water system. More information here.

Where are Backflow Preventers usually installed?

Generally, backflow preventers can be found on the main incoming water line into the building. If the building has a sprinkler system, the very first component in the sprinkler system will be a backflow preventer. Backflow assemblies can be found in several locations throughout a building, Depending on the hazards that are present, individual water consumers may be protected by their own assembly. Some examples would be pools, ice machines, dishwashers, and other applications where water is mixed with chemicals. Backflow hazards range from minor to severe, depending on the effect the contaminated water can have on human health.

How does a backflow preventer work?

Backflow preventer assemblies are comprised of two one-way valves, referred to as check valves. These valves close when no water flow is present and thus restrict the reverse flow of the water. As there is two valves, there is a level of redundancy built into these devices. This redundancy ensures that the public water is still protected, even if one of the check valves has failed.

To learn more about backflow preventers, the American Water College has an excellent video demonstrating the functionality of a backflow preventer. Find it here.

There are several other components to a backflow preventer, such as the shut-off valves and test cocks, to provide a means of testing the assembly. There are two main backflow preventer types in use today, though there are about 15 different types altogether. The two most used are:

DCVA – Double Check Valve Assembly

  • The most common type of backflow prevention aseembly.
  • Suitable for minor-hazards. The American Water Works Association (AWWA) defines this hazard as a situation in which a cross-connection might create a nuisance or be aesthetically unpleasant but would NOT create a health hazard.  
  • The main parts of a DCVA are an inlet shutoff valve, two independently operating spring-loaded check valves (usually inside a single valve body), four test cocks, and an outlet shutoff valve. 

RPZ – Reduced Pressure Zones

  • More reliable than a DCVA, but also more elaborate.
  • Generally required for severe-hazard settings, defined by the AWWA as those in which an unprotected cross-connection could introduce substances capable of causing illness, death, or disease spread if introduced into the public water supply. 
  • Equipped with a relief valve in addition to two spring-loaded check valves. The relief valve will dump water in the event of a check valve failure, to ensure the water supply is protected.

Testing Requirements

Testing of backflow assemblies is generally required by the water authority. The American Water Works Association (AWWA) otulines the certification requirements for qualified technicians. Testing of an assembly is generally required every year, though some municipalities may require it more frequently. All testing needs to be completed by a qualified professional.

A backflow test involves a simulation of a backflow event with a specialized gauge under protected conditions. This will yield a test result indicating the functionality of the unit. If there is backflow, meaning water flowed back through the unit, it must be repaired or replaced immediately. Most backflow can be repaired, which involves gaskets and the check valves themselves. In some cases the entire backflow preventer may need to be replaced.

It is important to work with a qualified professional when it comes to backflow preventers. Incorrect installations or repairs can cause premature failures. Incorrect testing may also damage the units and without the necessary certifications, your water authority may reject the tests altogether. Regular testing of the backflow assemblies is crucial, as the liability for contaminating the water supply is ultimately your responsibility.

Nexus Fire & Safety can help you meet all your backflow testing requirements and offer the most cost-effective approach should one or more of your assemblies fail testing. Our technicians are fully certified and can assist with the design, installation, inspection and maintenance of all your fire safety systems, including backflow preventers. Get in touch today to learn more

Where to place a Carbon Monoxide Detector

Open Flame on a Gas Range

Carbon Monoxide (CO), also referred to as the silent killer, is a real danger. Canada experiences 300+ Carbon Monoxide related deaths every year. Research shows that, just like smoke alarms, Carbon Monoxide detectors can save lives.

What is Carbon Monoxide and where does it come from?

Carbon Monoxide is a gas that is created from an incomplete combustion process. Carbon monoxide can be created by fuel-burning appliances, such as furnaces or gas ranges. It is a odorless and colorless gas. If inhaled, the carbon monoxide gas will bind to the hemoglobin in the blood and will deliver carbon monoxide instead of oxygen to the cells.

Hemoglobin, or also the red blood cells, is about 250 times more likely to bind with carbon monoxide than oxygen. Once bound with the CO molecules, it is extremely difficult to remove them from the bloodstream, which is why you should always seek medical assistance after exposure.

Symptoms of Carbon Monoxide Poisoning

Carbon Monoxide is difficult to detect, as it does not smell and cannot be seen. The symptoms from the on-set of CO poisoning are similar to the flu, except for the fever:

  • Headache
  • Fatigue
  • Shortness of breath
  • Nausea
  • Dizziness

As the level of CO poisoning increases, the symptoms will also worsen.

  • Mental confusion
  • Vomiting
  • Loss of muscular coordination
  • Loss of consciousness
  • Ultimately death

The severity and speed at which these symptoms progress will depend on the duration and exposure. Taking a full breath of CO can lead to immediate death, as happened during a mining disaster.

What levels of CO are dangerous?

The levels at which symptoms are noticed will largely depend on the individual’s health condition. Carbon monoxide concentration is measured in parts per million (ppm). Between 1 and 70 ppm, most people will not experience any symptoms. An increase above 70ppm is when symptoms will start becoming noticeable. Sustained exposure to concentrations above 150ppm to 200ppm can lead to unconsciousness and ultimately death.

Where to place a Carbon Monoxide Detector?

There is a common misconception that CO will drop to the floor, as it is heavier than air. Carbon Monoxide is marginally heavier than air; that part is correct, though, with the small marginal weight difference, it mixes with the air and will be present at all heights. Thus mounting a carbon monoxide detector can be done high up on a wall or plug-in style detectors at the nearest receptacle can also be used. Locate the detectors in hallways outside of bedrooms. It is not recommended to place them close to fuel-burning appliances.

What to do if the Carbon Monoxide Alarm Sounds

The sound for a CO alarm is generally a temporal four pattern. That means four beeps with a 1-second pause after the beeps. Some CO alarms will also announce the alarm condition with a voice prompt.

If the alarm sounds, NEVER ignore it and NEVER try to find the source of the problem. It is informing you of a potentially life-threatening situation. When the alarm sounds:

  • Immediately move outside for fresh air.
  • Call your emergency services, fire department, or 911.
  • After calling 911, do a head count to check that all persons are accounted for. DO NOT reenter the premises until the emergency services responders have given you permission. You could lose consciousness and die if you go in the home.
  • If the source of the CO is determined to be a malfunctioning appliance, DO NOT operate that appliance until it has been properly serviced by trained personnel.

How to test a CO Detector

Testing a carbon monoxide detector is very similar to testing a smoke alarm. Most units will have a test button. Note that testing the detector only test the internal circuitry and not the sensitivity of the detector. That is why it is important to replace these detectors upon their expiry. To test a CO detector:

Smoke Alarm Test Button being Pressed
Regular testing is important.
  • Press the button on your alarm and keep it pressed down. The alarm should sound. If interconnected, the other alarms should sound as well.
  • If your alarm has no button, it is outdated and must be replaced.
  • Follow the manufacturer’s instructions on testing and maintaining your alarm.
  • Check the expiration date on the side or back of the device. If there isn’t one, replace it.

If the alarm fails to sound or the alarm is past its expiration date, we recommend it be immediately replaced. We also recommend that you blow any dust that may be present within the casing out of the unit every year. This will minimize false alarms and maximize its detection potential. When replacing a line-voltage or 120V unit, please ensure to hire qualified personnel, such as Nexus Fire & Safety to make sure the device is replaced properly and safely.

Nexus Fire & Safety carries a large stock of smoke alarms and is ready to assist with replacing any outdated units that you may have. We have electricians on staff that are more than qualified to assist with any new installations or replacements of the devices. Additionally, we can provide design assistance for placement and answer any general fire safety questions you may have.

How to use a Fire Extinguisher – P.A.S.S.

Should a fire ever happen, it is important to have a fire extinguisher at the ready. But without any idea how to use it, it could be more dangerous to use the extinguisher than to just run the other way. The most important part to using a fire extinguisher is to only use it when it is safe to do so. If it is not safe to fight the fire, leave the area immediately and dial 9-1-1.

That means that you know how to use an extinguisher. It also means that you have a clear exit path in the event that you are unable to extinguish the flames, allowing you to escape. If there is any doubt about the escape path, whatsoever, evacuate the building immediately. Lastly, the fire needs to be small enough to be fought by a fire extinguisher, use your best judgement for that, but again, when in doubt, evacuate and wait for first responders.

All fire extinguishers have operating instructions printed on their label. Most of them list the order of operation with the PASS Method. This is the same method that we are going to explain in this article. It is important to be familiar with it and know it instinctively.


In order to use a fire extinguisher to fight a fire, you need to locate the closest one. Be familiar with the building and take a look at any extinguishers you walk past. Not only are you familiarizing yourself with their locations, but also are performing preventative maintenance. Fire Extinguishers rely on their charge, which is indicated by the pressure gauge. Should that be depleted (in the red), then there is a problem that needs to be addressed. In looking at the fire extinguishers regularly, you notice these things.

Using the correct extinguisher for the fire is also important, as an extinguisher can be ineffective, or worse become a hazard to the user. Being familiar with the different classes of fire and the appropriate fire extinguishers for them should be a priority.

Fire Extinguisher P.A.S.S. Method

The PASS Method was created to make it easy to remember how to use a fire extinguisher. Using an extinguisher really is quite easy, though in an emergency situation, even the simplest concepts can become difficult. After locating the closest extinguisher and removing it from its wall bracket or housing, you would follow the steps of PASS:

P.A.S.S is an easy way to remember how to use a Fire Extinguisher

Pull the Pin

All Fire Extinguishers have a safety pin installed in the handle. This prevents it from accidentally being activated. The pin should always pull to the left and be secured with a tamper seal. Should the seal be missing, it may indicate tampering and the extinguisher should be replaced with a known functional one. The Pin itself should be quite lose and only secured from sliding out by the tamper seal. Any other object, such as a Zip Tie in place of the tamper seal, or a nail instead of the Pin are prohibited. Replacing the Pin or the Seal with anything but the approved parts, can prevent the extinguisher from functioning.


Once you have the extinguisher at the ready, aim the nozzle towards the Base of the fire. Most fire extinguishers work by blanketing the fuel of the fire, or by cooling the fire. That’s why it is important that the base of the fire gets the most of the extinguishing agent.


Squeezing the trigger is the next step. When squeezing the trigger, make sure you are holding the nozzle firmly and are not covering the nozzle opening. Keep squeezing the handle for as long as the extinguisher is discharging. This ensures that all possible extinguishing agent is used. Note that the average extinguisher will only spray for about 10-25 seconds. That’s why it is important not to overestimate the extinguishers fire fighting capabilities.


When the fire extinguisher is discharging, sweep the nozzle across the base of the fire. By sweeping, you ensure that the base is evenly covered with the extinguishing agent. Start from a safe distance from the fire and move closer as the extinguisher fights the fire. Once the fire is extinguished, keep an eye on the area. Fires can re-ignite even after having been extinguished.

Deciding to Fight the Fire with a Fire Extinguisher

To reiterate, if you have any doubts about your ability to use a fire extinguisher or that you can be effective in fighting it – Evacuate the building immediately.

A fire extinguisher should only be used in the following scenario:

  • the fire is in its early, incipient stage
  • you have the right fire extinguisher for the class of fire
  • you have a safe exit path

If the fire extinguisher fully discharges prior to extinguishing the fire, exit immediately and do not continue fighting it, if it develops past its incipient stage. Your safety should always be at the forefront of every fire fighting decision you make.

What if my Smoke Alarm is beeping

Smoke Alarm on Yellow Background

What is a smoke alarm?

When it comes to smoke alarms, there is a common misconception. A smoke alarm is an all-in-one device that will sound an alarm when it detects smoke. They are different from the smoke detectors connected to fire alarm systems. You can find smoke alarms in residential homes or apartments. They are also found in sleeping quarters in hotels and other camp-style accommodations.

Smoke alarms encompass different technologies to detect smoke, which are covered here. They sometimes come as combination units that can detect carbon monoxide within the same device. Many of these devices are battery-powered, while others are connected to the 120V supply of the building. If the smoke alarm is a 120V connected device, they can often interface with other alarms to sound throughout the home.

How to maintain a smoke alarm

Smoke alarms, like any piece of technology, should be appropriately maintained. With the proper maintenance, smoke alarms can save lives. The maintenance of these alarms is quite similar, no matter the detection technology or power method. Testing should be completed at least monthly by following these steps:

Smoke Alarm Test Button
  • Press the button on your alarm and keep it pressed down. The alarm should sound. If interconnected, the other alarms should sound as well.
  • If your alarm has no button, it is outdated and must be replaced.
  • Follow the manufacturer’s instructions on testing and maintaining your alarm.
  • Check the expiration date on the side or back of the device. If there isn’t one, replace it.

If the alarm fails to sound or the alarm is past its expiration date, we recommend it be immediately replaced. We also recommend that you blow any dust that may be present within the casing out of the unit every year. This will minimize false alarms and maximize its detection potential.

Regular false alarms can be a detriment to these life-saving technologies, as they desensitize the occupants of the sound. With the alarm regularly sounding, people will automatically assume it a false alarm, which may cost them their life. When replacing a line-voltage or 120V unit, please ensure to hire qualified personnel, such as Nexus Fire & Safety to make sure the device is replaced properly and safely. When replacing interconnected devices, it is important to replace all units with the same make and model, to make sure the interconnection continues to work.

Why is my alarm beeping/chirping?

Smoke alarms are built with fail-safes to provide a warning if something is malfunctioning. For battery-powered or battery-backup devices, the unit will start chirping if the battery is low or missing. For line-voltage or 120V powered, the units will often chirp if line voltage is lost during a power outage. This is used to indicate that the unit is on its battery backup and may power off if power is not restored to it.

All detectors have an expiry date, which is usually 10 years, but as short as 5 years for some brands and types. Many of these detectors will start beeping in regular intervals, once every minute or something of the sort. If there is no expiry date or if the data has passed, we recommend the smoke alarm be replaced immediately.

A beeping or chirping alarm is not just an annoyance, but it is trying to tell you that something is wrong. We recommend immediate action be taken as it is a life-safety device and should be maintained to the highest possible standard. If in doubt as to what the beeping is indicating, consult the manufacturer’s manual, which should be available on their website.

Nexus Fire & Safety carries a large stock of smoke alarms and is ready to assist with replacing any outdated units that you may have. We have electricians on staff that are more than qualified to assist with any new installations or replacements of the devices. Additionally, we can provide design assistance for placement and answer any general fire safety questions you may have.

Are All Fire Extinguishers Created Equal?

Hand Holding Fire Extinguisher Handle

Fire Extinguishers are around us all the time and we should always know where the nearest one is. All extinguishers, however, are not created equal. There are different sizes and different types of fire extinguishers intended to fight different classes of fires.

To be truly fire smart, the right fire extinguisher has to be installed in the right location. This will maximize the effectiveness of a fire extinguisher in the event of a fire.

Fire basics and why the type of fire matters

Fire Tetrahedron – Elements required for Fire

The theory of fire is based on what is called the Tetrahedron. It outlines the four elements required for a fire to be present. By removing one of these elements, the fire cannot continue and is thus extinguished. The four elements are:

  • Fuel
  • Heat
  • Oxygen
  • Chain Reaction

A fire extinguisher works on the principle that it will remove one or multiple of these elements and stop the fire in its tracks. There are different types of fuel for the fire and that is where the different classes of fire extinguishers come in. The reason for the different classes becomes quite obvious with the example of using a water extinguisher on an electrical fire. This will cause a hazard to the user.

There are five main classes of fires, which we will discuss further in this article.There is a specific extinguisher for each class and some cover multiple classes. The classes are:

  • Class A – Ordinary Combustibles, such as paper or wood
  • Class B – Flammable Liquids, such as gasoline
  • Class C – Live Electrical Fire – Serves as the cause for a Class A or B fire. If the electrical is removed, it is no longer a Class C fire.
  • Class D – Combustible Metals, such as Magnesium or Sodium
  • Class K – Grease Fires

Types of Fire Extinguishers

With a basic understanding of fires and why different fire extinguishers are necessary, let’s discuss the six main types of extinguishers and their uses:

A-B-C Fire Extinguishers

ABC Fire Extinguishers contain a fine powder, commonly mono-ammonium phosphate. It is the most common fire extinguisher found in just about every building. This type of extinguisher has the advantage that it is highly versatile as it can be used on Class A, B and C fires. The principle and ABC extinguisher operates under is that it blankets the fire and aims to starve the fire of its Oxygen. The powder is not an electrical conductor and can effectively interrupt the chain reaction in a gas or liquid fire.

Wet Chemical Fire Extinguishers

Wet Chemical Fire Extinguishers primarily fight Class K or grease fires. The chemical inside of a Class K extinguisher is a solution primarily composed of potassium, which fights the fire in two separate ways. The chemical will act to cool the fire initially, starving the fire of the heat component. Upon contact with the grease or cooking medium, the chemical starts to foam and blankets the area, which is intended to prevent re-ignition of the fire. While we chemical extinguishers are your perfect choice for a kitchen, they can also be effective on Class A fires.

Water-mist Fire Extinguishers

Water Mist Fire Extinguishers are the newest type of fire extinguisher. These extinguishers work across almost all classes of fire. When used, the water fire extinguisher releases a fine mist of water, which attacks several elements of the fire tetrahedron.

First, it starves the first of oxygen, as the fine water particles take up space and decrease the oxygen levels near the fire. Second, the water will cool the fire and affect the heat component, as water naturally does. What is unique about water extinguishers is that the water generally has had all minerals removed (de-ionized), which means it can also be used on electrical fires, as it does not act as a conductor. That means that water fire extinguishers are effective for Class A, B, C and K fires.

Clean Agent Fire Extinguishers

Clean agents are a type of gas fire extinguisher. The extinguisher contains a liquid, which, when discharged, will convert to its gaseous form. The gas is non-conductive, leaves no residue and dissipates very quickly which makes it Eco-friendly. The gas used is usually a Hydrochlorofluorocarbon, marketed as Halotron. The extinguishing agent reduces the oxygen levels and impedes the chain reaction of the fire. As it doesn’t leave any residue, it is ideal for server and electrical equipment or Class B and C fires.

Carbon Dioxide Fire Extinguishers

A CO2 Extinguisher is another type of clean agent extinguisher, as it does not leave any residue. The extinguisher disperses the oxygen from the fire and replaces it with the CO2 contained within. This effectively suffocates the fire, making it the perfect choice for Class B and C fires.

Foam Fire Extinguishers

A foam extinguisher contains a liquid, which foams and expands upon contact with the air. The foam then blankets the fire, which starves the fire of its fuel. The foam has a cooling effect as well, as it does contain some water. Foam extinguishers can be used on Class A and are excellent for Class B fires, though lose their effectiveness for gaseous fires.

Are you protected?

Now that you have more information about the types of fire extinguisher that are out there, take a look around and see what fire extinguishers your business has. Make sure you have a fire extinguisher for every hazard class that may be present in your facility.

Another important aspect to fire extinguishers and fire safety is getting the extinguishers maintained and inspected, and ensuring everyone is properly trained on how to use a fire extinguisher.

Nexus Fire & Safety can assist with fire extinguisher layout and ensuring the right extinguisher for the hazard is present. Our team is fully certified and can provide training for your staff. We are also equipped to maintain and test your fire extinguishers, ensuring they are ready for use, should you need them.

Kitchen Suppression Inspection – What to Expect

Pan on Fire in Commercial Kitchen

Kitchen Fire Suppression systems are the heart of fire protection for commercial kitchens. Due to the presence of grease, an inspection of the fire suppression system has to be performed every six months. In this article we outline what to expect during a Kitchen Fire Suppression inspection and how to prepare for it. A kitchen that is ready to be inspected allows us to complete the inspection more efficiently and keeps your staff, as well as our technicians safe.

Preparing for a Kitchen Fire Suppression Inspection

Our scheduling team at Nexus Fire & Safety will reach out to you to schedule your inspection. Ideally pick a time before any cooking activities are started and when a minimal number of kitchen staff is present. This ensures that our technicians have enough space to complete the inspection and we are not in anyone’s way when they’re trying to cook.

If the building your kitchen is in has a fire alarm system, there is a good chance the Kitchen Fire Suppression system is connected to the fire alarm system. Please ensure that you have contacted the necessary parties, such as a building manager, to allow for access to the fire alarm. Additionally, make sure you have the monitoring information for the fire alarm ready, so our technician can put the system on test.

The areas that our technicians would need access to are:

  • Kitchen Hood
  • Gas Valve (Generally located close to the kitchen hood)
  • Fire Alarm System
  • Electrical Panel

Please ensure that these areas are readily accessible, as they may need to be accessed multiple times.

Most time for the inspection is spent under the hood. Any appliances should NOT be turned on before inspection. This keeps our technicians safe from potential burn hazards.

What to Expect During a Kitchen Fire Suppression Inspection

Kitchen Fire Suppression inspections follow a rigorous process to meet UL(C) and manufacturer standards. The steps are very similar between system manufacturers. Upon arrival our technicians will follow the following steps every time:

  • Contact Monitoring and Bypass Fire Alarm (if applicable)
  • Deactivate Suppression System
  • Locate Gas Valve and Link Lines
  • Test System Actuation
  • Inspect System Setup and Replace Fusible Links
  • Test Pull Station Actuation
  • Reset System
  • Re-Arm System
  • Reset Fire Alarm System (if applicable)

During this process, some pressurized test cylinders may be discharged. Additionally beeping and loud mechanical noises may be heard. These are perfectly normal and are part of every inspection. Prepare your staff that these inspections are happening and of the possible sounds. This ensures that no one takes the initiative to call the fire department, as it is only a test.

Upon completion of the tests, our team will walk you through any of our findings. A report will also be provided and the system will be tagged with an inspection tag, outlining the services that were performed.

Why do I need an inspection?

Kitchen Fire Suppression Inspections are a crucial part to ensuring the fire safety of your kitchen and the building around it. Kitchens have many fire hazards present with open flames, grease, flammable liquids and solids. Ensuring the system that is going to protect your business and staff in the worst case scenario is important.

Fire Suppression System Fusible Link

Kitchen Fire Suppression systems are mechanical systems and thus are not perfect. With an inspection every six months, the risks of a system failure a minimized. Failures can stem from a greased up component, a damaged cylinder or something stored in the wrong place, preventing access. Most Kitchen Fire Suppression systems work with fusible links. These are metal components designed to melt when a specific temperature is reached. These links require replacement, as they get coated with grease and debris, which may affect their temperature ratings.

With an inspection, all of these factors are inspected and should anything be amiss, it will be documented and addressed. An inspection will also minimize the risk of an accidental discharge of the system, which may save you a significant amount in the future.

Nexus Fire & Safety is fully certified to install, service and repair Kitchen Fire Suppression systems. Our team is ready to answer any questions that you may have and will ensure you have the best experience possible with every inspection. Call us today if you have a Kitchen Fire Suppression system in need of servicing or any questions related to fire safety.