Why Didn’t That Burn Down?

Across the world, people are breaking out their air conditioners, fans, and everything they can find to keep cool. Along the way, a few people are going to flip the big switch and have things go wrong. There might be a brief grinding sound before sparks start flying or a loud bang from a worn capacitor blowing it’s top, but nothing deadly happening, just scary things. Things weren’t always built like that. Once upon a time, when things went wrong, they took people with them. Burning Equipment In the early years of electrical equipment, there were no standards or best practices. Electrical fires could be caused by faulty wiring or just faulty-designs. If something like a fan became seized up, there would still be power flowing into it. More power is more heat. Eventually more heat is going to lead to fire or electrical arcing and things are going to go wrong fast. There could be appliance casings made of metal, with no protections from ground shorts. A power drill could short to its casing and electrocute the user or catch something on fire. There weren’t even ground pins available on most electrical outlets at one point in time, leaving one less degree of electrical protection. When things went wrong in the old days, they would generally fail with flames or explosions, fail deadly. Modern Safety Standards When things go wrong, insurance companies are often left with the bill. This […]

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Fire Safety in Live Systems

Industrial and residential settings increasingly have one big thing in common: you can’t eliminate all the hazards. When a fire breaks out, we want our buildings and our equipment to default to a “safe” state. We want to shut off gas valves, kill electrical breakers, and get anything explosive like propane bottles and gas cans as far from the fire as possible. Unfortunately, some situations are not this simple.   Standard Residential Procedure When a house fire breaks out, the fire alarm goes off, you evacuate, and at some point the local emergency dispatch center hears about it and dispatches fire fighters, police, and EMS. Their first priority is to get everyone out alive. Along with that they need to prevent the fire from spreading to nearby fields and buildings. Lastly they’ll try to save as much of the structure as possible, but sometimes all they can do is watch it crumble. The process of actually handling a fire is a multi-stage exercise in chaos. On scene, fire fighters need to run hose line to spray water, teams have to enter the building to locate trapped victims. Part of the crew has to set up a constant water supply, either from a hydrant or a relay team of tankers that will drive a circuit between their fill station and the fire. Along the way, the fire fighters need to ID and remove as many hazards as possible. They’ll go right […]

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What Happens to Fire Alarms in a Power Outage?

Fire safety is serious business. We’ve covered how alarm panels, their sensors, and the entire sprinkler system are designed to survive the end of the world. This extends beyond the panel itself and straight on to the infrastructure that runs it. Even during a power outage, most alarm systems will continue to function perfectly.   The Battery Backup Most alarm systems have an integrated back up for when the power grid, or even building power supply fails. On the whole, an alarm system is a really low-power set up, making it ideal for battery operation. The fire panel itself is mostly a massive input/output complex, with just a handful of memory chips and processors doing the heavy lifting. In an extremely simplified sense, you could imagine the fire panel as a cell phone mother board, wired up to a massive sensor system. The battery powering your cell phone is pretty tiny, but yet it keeps your phone chugging along for 12-48 hours, depending on the model and how exactly you use it. Now just imagine a bigger, simpler lead-acid battery, and it’s also powering a couple hundred smaller sensor devices, with cell-phone like processors in them. That is the situation inside most fire panels and other similar safety systems. In most cases, local fire codes requires these alarms to function for about 24 hours on batteries alone. Given we’ve seen countries like Puerto Rico go dark for months from natural […]

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What Does a Fire Alarm Panel Control?

Do you know how much control that alarm box has? Have you seen just how deeply it’s wires invade the systems of your building? This is another essential, modern miracle of engineering. When things go wrong, we can use every component of a building to get people out safely.   Alarm Misconceptions Most people look at the fire alarm and think it’s just like in the movies. On the big and little screen, we’ve portrayed our safety systems as being pretty dumb. You pull the alarm and suddenly the entire building is in a gentle rain and a bell dings. There probably are systems like this in the world, but most don’t quite work like that and it’s not the full story. In its simplest terms, your alarm system is a big noise maker. In modern terms, it’s a full-on building automation system in a box. Your building is a complex intertwining of separate, complex systems. You have the air ducts which blast fresh, cold air into the rooms during the summer. You have water pumps and boilers supplying water. There’s electrical breakers, elevators, and maybe even RFID-Tag/Key fob/pin-code access doors all over. Every one of these components is going to pose a problem when a fire breaks out. What do you do if someone’s in the elevator, and the fire is in the elevator mechanical room? What do you do if there’s an air vent blasting cold air into […]

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Fool Resistant Design in Fire Sprinklers

Today we have a funny story and a bit of a humorous take on why concealed sprinklers are better than exposed sprinklers. Let’s first cover a bit of background on these sprinklers and where the big problems come in.   Anatomy of a Fire Sprinkler Sprinklers are designed to be nearly fool proof and as close to failure proof as possible. This means they have to be simple and physics have to be the main source of actuation. To start with, you’ll have all the sprinkler piping, which is pressurized, often by gravity pulling water downwards from higher floors and by the pumps keeping the system full and ready to go.  There’s enough force on the water to dump 100+ gallons per minute for several minutes after a sprinkler goes off without needing any additional pressure from the pump. The sprinkler head itself is a work of genius. The pipe comes up to it, and it’s blocked off by one of two things: a bi-metal plate or a vial of typically red fluid. These are things we can design to break in response to heat. When they break, water blasts out, hits a spreader, and is blasted out over several feet around the sprinkler head. This is almost as fool proof as something can ever be. Fire means heat and heat rises. There’s almost no scenario where there can be a fire that the sprinklerhead won’t break. You can choose […]

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Electrical Fire Safety

There are a ton of safety devices that are preventing you from being shocked, from starting fires, and from destroying expensive equipment. The problem is, no matter how many safety devices we put in the building, something is always going to go wrong. When things go wrong, it’s essential to be prepared for the absolute worst.   Causes of Electrical Fires The absolute root cause of electrical fires always comes down to energy. The copper wiring carries electricity, electricity is energy. The movement of electricity always creates heat. More electricity means more heat. When things go wrong, there’s too much electricity or not enough insulation to contain the electricity, or some other fault that allows heat to build up or electrical arcs to occur and start a fire. This can happen any number of ways. There can be an electrical short, perhaps water getting into a non-GFCI bathroom or kitchen outlet. There could be something shoved into a socket that really doesn’t belong there, thanks to an overly curious toddler. There can be corrosion, causing an electrical short. It could even be down to a cheaply made product skipping out on essential internal safeties (this happens more often than most people realize). In all of these cases, there’s going to be a battle on two fronts.   Stopping the Power and the Fire If you’re not quite thinking straight, you might try to extinguish an electrical fire with water. The […]

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What Causes Electrical Arcing?

Most everyone in the world has seen an electrical arc. Lightning, certain short circuits, and other times when there is literally electricity moving through the air are all Arc Flashes. We’re going to look into the fundamental causes of electrical arcing.   Moving Power Electricity is essentially a charge being conducted through a wire. All electrical charges want to disperse as quickly as possible. They’re like water behind a dam: it always wants to get out. In the case of electricity, the charge wants to disperse, positive to negative. It always wants to get to ground. The problem with this is that we want to actually use the electrical charge, so it can’t go straight to ground. We use insulators to keep the electricity essentially safely inside the wire. Without the insulator, the charge would get out and work it’s way to ground like water out of a burst pipe following gravity. Insulators can be a wide range of things. The rubber casing around wire is it’s insulator. The gigantic, ceramic cones on utility poles are insulators that prevent the charge from trying to discharge into the wooden pole. The air itself is also an insulator. Electricity generally does not want to move through the air. This is why we can have electrical sockets exposed to the open air, but not to water. The air won’t easily conduct an electrical charge but the water will. Water isn’t a great conductor, […]

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Common Electrical Safety Devices

How do we stay safe with electrical failures? We’ve covered a bit about how grounding is essential. When there is an excess of electrical power, send it to ground. This is not the end of the problem. If there is a physical fault or a problem with the incoming power supply, we need to cut off power altogether. Surge Protectors These are in many ways, the first line of defense. Surge protectors work mainly to protect equipment. In the event of electrical shorts, they may not protect you. There are numerous protection mechanisms inside. Some surge protectors use resistors, some have gas discharge tubes, others use special diode systems, dump the charge to ground, and more. The important thing to always keep in mind with surge protectors is that many surge protectors are power strips, but not all power strips have surge protection built in. In fact, surge protection exists as a whole corner of the industry all its own. There are large-scale surge protectors that can be built directly into buildings. These devices arrest and mitigate surges before they can cause damage and before a breaker or other safety device would have time to react. Ground Fault Circuit Interrupters There should be as much current, as many amps coming back into an AC Outlet, as leave it. If the current coming back into an outlet is significantly less than the outbound current, that energy must have gone somewhere. Running […]

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Why is my Building Grounded to the Water?

In the US, we commonly have three prongs for our electrical devices. Two of these deliver the AC Current, being both positive and negative over time and a third which goes to Ground. This is a safety thing. Whenever there is an electrical short, a static build up,  or even a lightning strike, we want to divert that somewhere safe. The safest place for these excess charges is straight to the Earth, the ground below us. As big as the Earth is, it basically has an absurdly powerful negative charge. You can disperse power into the ground and it’ll dissipate safely. Getting to Ground It is essential for every electrical and metal component of a building to be grounded. This can be a real nightmare to actually implement. You need something that is going everywhere in the building. On the one hand, you could run additional conductors, miles and miles of additional conductors, or you use the one conductor that’s already there: the water pipes. That’s right, older buildings ran their electrical grounds straight to the plumbing. On the one hand, this does kind of work. The copper pipes in most buildings are excellent conductors. These pipes are going to make contact with the ground at some point. If there’s a well, the pipes are going deep underground. If there’s municpal water, they’re still going to be several feet below the surface before long. For the early days of electrified […]

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