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.

Prerequisites

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.

Aim

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.

Squeeze

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.

Sweep

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.