What Are the Basics of Fire Sprinklers?

One of the most important innovations in fire protection engineering has been automatic fire sprinkler systems, which not only save countless lives but also reduce the severity of fires across the globe. They are extremely effective in containing fires and allowing occupants time to escape as well as firefighters time to respond.

The first step in understanding sprinkler systems is knowing where the water supply comes from.

Sprinkler systems start with the water supply and end at the sprinkler head. The water supply can be a municipal water system, a water tank, or even a river or lake! The authority with jurisdiction determines what an adequate and reliable water supply looks like for their specific application. For instance, a fire sprinkler system for a dam might be able to use water from its own reservoir. Another example of an alternative water supply is a rural home with well water that can utilize its own water tank as a source for a fire sprinkler system.

The second step in understanding sprinkler systems is to recognize how the water reaches its final destination.

The next part of a fire sprinkler system is the piping from the source to sprinkler riser. This is usually done as underground piping but can also be done aboveground. Either way, the piping must be restrained properly, as the sudden force of a large volume of water can rip apart the piping, particularly at the bends. The bends are typically reinforced with concrete thrust blocks, a mechanical joint restraint, tie rods, or a combination of all three. An important consideration with underground piping is corrosion, but sacrificial anode bags can be used to delay the corrosion process. A backflow system is usually incorporated into the source piping to prevent contamination to the main source of water.

Next, you will want to know what the sprinkler riser is as well as its function in the fire suppression process.

The sprinkler riser is a vertical pipe that connects to the main branch of the sprinkler system and brings the water from the source piping to the overhead sprinkler system. The riser contains many parts, including a control valve, check valve, waterflow switch, a test drain, and various pressure gauges. The control valve is essentially a shut off valve that can be used to turn off the sprinkler system once the fire has been extinguished. The check valve prevents water from returning to the underground system. The water in the sprinkler piping is usually putrid as it has been in the system for many years without movement, and that water should not return to the source. The waterflow switch sends a signal to the fire alarm system when water is moving through the system. This indicates a serious situation and is usually transmitted to the dispatch center who will then get the fire department rolling to the site. The test drain allows an inspector to measure the flow and pressure from the system without actually setting off any heads. Pressure gauges show the working pressure of the system and tell the inspector if the system is still within its design parameters.

The first line from the riser is called the main line and is usually the biggest sprinkler piping line in the system. It diverges into branch lines which bring water to individual sprinkler heads. The main and branch lines need to be properly restrained in the event of an earthquake or waterflow. As mentioned earlier, the sudden shock of high-volume water flow produces large forces on the piping which can break apart the entire system, so the piping is held in place by braces and hangers that are designed to withstand the force of flowing water.

The last step of understanding the basics of fire sprinkling systems is knowing the components of the fire sprinkler itself.

The fire sprinkler itself consists of a fusible element that breaks when heated to a certain temperature, which then releases a plug holding back the water. Once the water is released, it hits a deflector which creates a water spray pattern that will help control the fire. The amount of water and spray pattern is dependent on the hazard and is determined by the fire protection engineer. Most sprinkler systems have this type of sprinkler head that will only activate if it is exposed to heat, so the Hollywood trope of the entire sprinkler system going off in a building is entirely inaccurate!

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About the Author: Nick Tran

Nick Tran is a licensed Mechanical and Fire Protection Engineer in California. He has an Associates degree in Computer Aided Design from De Anza College, a Bachelor of Science degree in Mechanical Engineering from San Jose State, and a Master of Science degree in Fire Protection Engineering from Cal Poly SLO. He is currently on the UL Standards Technical Panel for UL 38 and was president of the Alameda County Fire Prevention Officers Association.

What Are the Basics of Fire Alarm Systems?

The most important aspect of fire protection engineering is occupant safety. The best way for a person to survive a fire is to get out of the building as soon as possible. A fire alarm system should not only alert occupants of a fire with an evacuation sound but also call the local fire department to extinguish the fire.

Table of Contents

1. Control Panels

2. Fire Detectors

3. Notification Systems

1. Control Panels

The "brains" of a typical fire alarm system is the control panel. The control panel receives inputs from detectors and decides what the outputs should be. For example, if the control panel receives a certain signal from a duct detector, it will shut down the associated air handling unit and send a notification for maintenance but will not necessarily sound a general evacuation alarm or call the fire department. However, if a control panel finds that the sprinkler system has been activated through a waterflow alarm, it will sound an alarm so the occupants can leave and notify the fire department. The ability of the fire alarm control panel to communicate with authorities is paramount-the sooner the fire department is notified, the faster they can fight the fire and keep it under control. Additionally, the fire alarm control panel can control other building systems, such as recalling elevators to the first floor or activating a smoke control system. The control panel is also a good resource for firefighters to find out where the fire has occurred, as many of them have displays telling which device has been activated. A fire alarm system might also have an annunciator, which is placed at the main entrance of a building to inform responding firefighters on the situation.

2. Fire Detectors

An aspect of fire alarm systems that many people are familiar with are fire detectors, as it is a requirement to have functioning smoke alarms in every residential structure. Smoke alarms provide an audible signal to alert occupants that they should evacuate. In fact, a smoke alarm helped save one of my relatives' homes from certain doom. They had forgotten a pot of food on the stove and left for work-after a couple of hours, the pot began to produce enough smoke to activate the smoke alarms. The neighbors heard the alarm and checked on the house. When they smelled smoke, they called the fire department who promptly arrived and saved the house from serious damage.

Every house should have a smoke alarm in each bedroom to save lives and property. For commercial applications, there are several types of detectors, including smoke, (which sense particles in the air), heat (which trip when a temperature threshold has been reached), and optical detectors (which pick up on infrared or other spectral bands). These detectors send a signal back to the fire alarm control panel. The type of hazard and environment will determine what type of detectors are used. For instance, in a sawmill, a smoke detector might activate constantly with all the dust in the air, so a heat or optical detector might be more appropriate.

3. Notification Systems

Once a detector has sent an alarm signal to the fire alarm control panel, the notification system will activate so that occupants can leave. The device that people are probably most familiar with is the horn/strobe, through which a light will flash and an audible signal will be emitted. Both the light and sound are designed to alert the occupant of the emergency. For high-occupancy buildings such as stadiums or concert halls, a speaker system may be used as well as strobes to provide exact instructions to the occupants. These systems, known as emergency voice/alarm communications systems, can guide occupants to the best exit and provide them more information on the emergency. These systems can also be used by the fire department for crowd control.

Fire alarm systems are integral to fire protection engineering. They save lives and property and give the responding fire department a head start in fighting the fire. Understanding these systems is essential for a safely built environment.

About the Author: Nick Tran

Nick Tran is a licensed Mechanical and Fire Protection Engineer in California. He has an Associates degree in Computer Aided Design from De Anza College, a Bachelor of Science degree in Mechanical Engineering from San Jose State, and a Master of Science degree in Fire Protection Engineering from Cal Poly SLO. He is currently on the UL Standards Technical Panel for UL 38 and was president of the Alameda County Fire Prevention Officers Association.

What Are the Basics of Egress?

The main goal of safety in a built environment is to get occupants out of a building as quickly as possible in the event of an emergency. Fire protection engineers work to arrange exits in such a way that all occupants can leave safely before they are overcome by heat or smoke.

Table of Contents

1. Components of Egress

2. Egress Requirements Change Based on Number of Occupants

3. Egress Placement and Size Requirements

1. Components of Egress

The way to leave a building is defined as the means of egress, which is a continuous and unobstructed path from inside a building to the public way. The means of egress is split into three distinct parts: exit access, exit, and exit discharge. The exit access is the pathway leading to an exit. An example would be the path between cubicles to get to an exit corridor. The exit provides a protected path to the exit discharge. Corridors and stairwells are common examples of an exit and are often protected by fire walls. The exit discharge connects the exit to the public way. This can be an exterior path leading from the building to the public sidewalk. All three aspects are required for a means of egress to be code compliant.

2. Egress Requirements Change Based on Number of Occupants

Intuitively, the more people there are in a building, the more exits are required for egress. If there are 49 people or less in a room, only one exit is required. A space containing between 50 and 499 people requires two exits, 500 to 999 occupants require three exits, and an area with over 1000 occupants would require a minimum of four exits. The number of occupants that are allowed to be in a particular area is determined by the occupant load calculation. The occupant load calculation is performed by dividing the area by the occupant load factor, which can be found in the applicable life safety code (NFPA 101, IBC, local codes, etc.).

Using a business occupancy as an example, the occupant load factor according to the IBC is 150 square feet per person, so a 10,000 square foot office space can have a maximum of 66 people (10,000 square feet divided by 150 square feet per person). This also means there must be a minimum of two exits from the space. The square footage per person varies by occupancy type. For instance, a warehouse could have an occupant load factor of 500 square feet per person while an event center could have an occupant load factor of 15 square feet per person. Changes in occupancy are important to recognize because that same 10,000 square foot office space could be converted to an event center, which would increase the occupant load to 666 people (10,000 square feet divided by 15 square feet per person), and an additional exit would be required.

3. Egress Placement and Size Requirements

The locations of the exits must also be considered. Exits cannot be too close together; the exits in a sprinklered building must be separated by at least 1/3 the diagonal distance of a room, and that distance increases to 1/2 diagonal distance in an unsprinklered building. Exits cannot be obstructed or otherwise impeded by furniture or obstacles.

The width of the egress component must also be considered. For instance, two 32-inch doors would not be adequate to serve a concert hall with 400 occupants. Generally speaking, the width of the stairs and ramps can be found by multiplying the number of occupants by 0.3 and the width of the doors and other level components is found using a factor of 0.2. Therefore, the total width of doors required for the 400-person concert hall is 80 inches (400 times 0.2). This can be split between the two doors required, and one of the doors must be a minimum of 32 inches, which allows for passage of wheelchairs.

 Fire protection engineers must work with architects to determine the best ways to get people out in an emergency. Although fire suppression and detection systems are important, the goal is to evacuate the building before people are injured or killed. Ultimately, understanding the basics of egress will help save lives.

About the Author: Nick Tran

Nick Tran is a licensed Mechanical and Fire Protection Engineer in California. He has an Associates degree in Computer Aided Design from De Anza College, a Bachelor of Science degree in Mechanical Engineering from San Jose State, and a Master of Science degree in Fire Protection Engineering from Cal Poly SLO. He is currently on the UL Standards Technical Panel for UL 38 and was president of the Alameda County Fire Prevention Officers Association.

Why Become a Fire Protection Engineer?

Why should you become a licensed fire protection engineer? There are several important reasons why you should consider becoming a fire protection engineer, including societal impact, room for growth, and salary.

Fire protection engineering is unique in that it is the only engineering discipline in which everything is governed around protecting life and property.

1. All the codes, research, testing, and development have one singular goal: ensuring the health and safety of people in the built environment.
2. It is often said that the life safety codes are written in blood, and this idea is mostly true.
3. As fire protection engineers learn more about fire dynamics and their impacts on human behavior, they continue to make changes in the relevant codes.
4. Many engineers are interested in how their company affects the world or the environment, and even in the private sector, most fire protection engineering companies offer a way to positively influence society while providing challenging and enjoyable projects.
5. No matter the type of work they do, a fire protection engineer will always be able to say they made a positive impact in their industry.
6. If you are interested in working in an industry whose sole focus is on making life safer, then fire protection engineering is for you!

Another reason you should consider fire protection engineering is the opportunity to grow and to make a mark on the industry.

1. The fire protection engineering community is relatively small and not saturated like civil or mechanical engineering.
2. In fact, in the state of California, there are only 800 active and licensed fire protection engineers, and of them, only 300 reside in the state.
3. This means that if you are passionate about engineering, you will likely stand out amongst your peers and at the very least, you will be recognized by your peers as a highly specialized and talented employee.
4. There is also a plethora of areas to explore in this field, including research, design, and code development. Fire protection engineering is a relatively new engineering discipline, with California licensing beginning in the late 1970s, compared to other more traditional disciplines, like civil which began licensing in the 1920s and mechanical beginning in the 1940s.
5. If you want to be a part of a burgeoning industry, fire protection engineering is for you.
6. Additionally, with the recent explosion of new construction, fire protection engineers are in demand now more than ever, which is an excellent segue to the next topic: salary.

While engineering in general is typically a lucrative profession, fire protection engineering can offer higher compensation because of the specialty and increased demand related to the position.

1. According to the Bureau of Labor and Statistics, fire protection engineers (often classified as health and safety engineers) are slated to make an additional $4,000 per year over mechanical engineers and $6,000 per year over civil engineers (https://www.bls.gov/ooh/architecture-and-engineering/health-and-safety-engineers.htm, https://www.bls.gov/ooh/architecture-and-engineering/mechanical-engineers.htm, https://www.bls.gov/ooh/architecture-and-engineering/civil-engineers.htm).
2. The job outlook is also rosy, as society becomes increasingly safety conscious, and more buildings are being constructed.
3. There are also many foreign companies that heavily recruit for fire protection engineers and offer additional perks and benefits such as paid housing and travel allowances.
4. Although satisfaction and recognition are important for any job, at the end of the day, we all need to pay the bills, and fire protection engineering provides fun and interesting career opportunities.

Engineering is noble and honorable work and is a great way to contribute to society while making a decent living. Fire protection engineering is no exception and magnifies the positive attributes of the engineering profession. If you are undecided about which discipline to get into, look no further than fire protection engineering!

About the Author: Nick Tran

Nick Tran is a licensed Mechanical and Fire Protection Engineer in California. He has an Associates degree in Computer Aided Design from De Anza College, a Bachelor of Science degree in Mechanical Engineering from San Jose State, and a Master of Science degree in Fire Protection Engineering from Cal Poly SLO. He is currently on the UL Standards Technical Panel for UL 38 and was president of the Alameda County Fire Prevention Officers Association.