Designing and Implementing a Fire Protection System

Q: How did the idea of ​​designing and implementing a fire protection system come about, and what are its main components? 

A: It arose from a market need, and the field continues to demonstrate growing demand while specialized personnel to service the segment are limited. Firefighting systems are diverse. They range from water-based extinguishing systems (the most common) to other systems that include CO2-based suppression systems, clean agent-based extinguishing systems, hybrid systems, and water-foam extinguishing systems.

 

The main components of a water-based extinguishing system are as follows:

 

• Pumping system.

• Water source (this can be a cistern, a tank, or even a reliable natural body of water, such as the sea).

• Piping and fittings to deliver water to the various systems where it is needed.

 

Other components include valves, sprinklers, nozzles, hydrants, monitors, hose stations, and supports.

In basic terms, hydrants are devices used to extract water and are directly connected to the general firefighting water system. Firefighters connect their 2-1/2" diameter hoses to supply their tankers and then travel to the location where they are needed.

There are two different types of hydrants: dry barrel hydrants and wet hydrants.

Dry-barrel hydrants are used in locations where temperatures are at risk of freezing (where temperatures reach 4°C or lower) and where there is a risk of getting struck by a vehicle. In contrast, wet hydrants are used in places where there is no risk of freezing (temperatures above 4ºC) or risk of being hit by vehicles.

 

Q: Regarding automatic sprinkler systems, what are their components, and what factors are considered when designing a sprinkler system.

A: Automatic sprinkler systems are a set of valves, pipes, fittings, and sprinklers (commonly referred to as risers). There are several types of automatic sprinkler systems, these include:

 

• Wet systems (all piping is filled with water)

• Dry systems (the piping to which the sprinklers are connected is filled with air or nitrogen, and the water is located before the alarm valve)

• Deluge systems (the piping to which the nozzles are connected is filled with air or nitrogen, and the water is located before the alarm valve)

• Pre-action systems (the piping to which the sprinklers are connected is filled with air or nitrogen, and the water is located before the alarm valve. An alarm and detection system is also required for activation and water flow)

 

The factors to determine what type of system should be designed depend on the characteristics of the enclosure to be protected. For example, if a cold room or a freezing chamber is to be protected, it would not be possible to install a wet system because the water inside the pipe would freeze, in these cases, a dry sprinkler system must be proposed.

Another example is protecting furnaces. Wet systems cannot be used because the water inside the pipe would be in a boiling state; in this case, a pre-action system or a dry system can be used.

Another case is when protecting a warehouse that stores various goods where the ambient temperature is 50ºC in summer. In this case, it is possible to propose a wet sprinkler system and we must select that the activation temperature of the sprinklers be at least 50ºF higher than the warehouse temperature.

For instance, when protecting an LP gas tank that is located outdoors, wet, dry, or pre-action systems are not appropriate. The ideal solution here is to propose a deluge system that ensures that in the event of a fire, water flows through the nozzles to prevent the tank from exploding.

 

Q: On the company’s website, it mentions that Delta Solutions’ services comply with NFPA, Factory Mutual, and/or NOM-002 standards. What do these standards entail?

A: The National Fire Protection Association (NFPA) is a non-governmental organization founded in the United States in 1896 that establishes standards and codes for fire prevention, electrical faults, and other issues. This organization has a high reputation, and its standards and regulations are accepted nationally and internationally because it has proven over more than a century that these standards work in fire suppression.

In addition, Factory Mutual (formerly FM Global) is an American insurance company founded in 1835 that has its own regulations and standards for fire prevention, construction, HVAC, electrical, and other industries. These standards, known as "Data Sheets," have a very good reputation for being reliable in extinguishing fires.

FM data sheets are used for design in plants or facilities where Factory Mutual is the insurer of the facility, since there are variations between what is stipulated by NFPA and by Factory Mutual (some are stricter).

Mexican Official Standards (NOM) are technical regulations that establish minimum occupational health, safety, and environmental conditions. These are applicable only in Mexico.

For fire extinguishing issues, NOM-002-STPS-2010 “Fire Protection Prevention” establishes the minimum requirements for fire prevention and protection in the country's workplaces.

 

Q: What are engine rooms, pump boards, and fire storage tanks?

A: Machine rooms are enclosures where fire pumping systems, hydropneumatic pumps, compressors, and other equipment are installed. Fire pumps are equipment used to move water from a storage tank, cistern, or other body of water to another location.

Pumps must be designed to deliver a flow rate and pressure greater than (+10 psi) what the most demanding area of ​​a fire extinguishing system requires. To determine a system's flow rate and pressure, a hydraulic analysis must be performed using mathematical formulas by hand or specialized software.

The panels or controllers are devices that control the pumping systems. Each pump must have its respective controllers, and from these, the pumps can be started, stopped, and tested.

A water storage tank is a water container for the fire system and must meet the following characteristics:

 

• Capacity to store between 60, 90, or 120 minutes (as appropriate) of the most demanding fire protection system

• Have anti-seismic anchors according to the seismic zone where it is installed

• Have a suction flange equal to or larger than the suction flange of the pump it supplies

• Have a manhole for service or maintenance

• Have a filling flange

• Have a drain flange and valve

• Have an overflow flange

• Have a level gauge

• Have a marine ladder to access the dome

 

Q: What is your smoke and heat detection system like?

A: It is a system comprised of, among other things:

 

• A central control panel, which can be intelligent or conventional

• Detectors (smoke, thermal, optical, laser, among others)

• Manual stations

• Audible alarms

• Visible alarms

• Backup batteries

• Power supplies

• Conduit (conduit and wiring)

 

There are input and output devices, and all are centralized by the panel. For example, when a smoke detector is activated (input device), it sends a signal to the panel, which then sends a signal to activate the audible and visible alarms (output devices).

 

Q. How often should a fire protection system be inspected?

A: I'm not a specialist in these matters, but I know that there are weekly, biweekly, monthly, quarterly, semiannual, and annual maintenance programs. There are two standards that address fire system maintenance (NFPA 25 and FMDS0281), which stipulate all the maintenance processes that must be considered to ensure fire systems are always in optimal condition when required.

 

Q: What happens when a sprinkler system is accidentally activated?

A: Sprinklers can only be activated for three reasons:

 

• Because the fuse or bulb has been accidentally hit

• Because the system is subjected to a pressure greater than the sprinklers can withstand (175 psi)

• Because there is a fire, and the resulting heat causes the liquid in the bulb or fuse to boil, causing the sprinkler to activate.

 

If the activation is by either of the first two scenarios, the main valve of the riser must be closed, the water trapped in the pipes drained, and the damaged sprinkler replaced with one of the same characteristics (K factor, the type of response, the type of coverage, and the activation temperature). After that, the main valve is reopened and the system is pressurized.

If the fire is activated by the third scenario, all personnel must be evacuated from the plant and the firefighters and the fire suppression system must be allowed to do their job. After extinguishing the fire, the sprinklers that were activated must be replaced, the tank or cistern must be refilled, and the pump must be checked for continued operation or replaced.

 

Technological Developments

 

Q: What recent advances exist in flame-resistant and fire-retardant materials?

A: Fireproof materials are those that retard fire and slow its spread. Some of these are:

 

Concrete

Firebreaks

Refractory bricks

Mineral wool

Fire-resistant glass

Fireproof polycarbonate panels

Ceramic coatings

Rock wool

Polyisocyanurate (PIR) foam

Stainless steel panels

 

The aforementioned materials are used in countless applications, such as doors, curtains, walls, and windows. The purpose of their application is to contain a fire for a considered time, thus giving time for the fire crew or trained personnel to extinguish the fire before it continues to spread.

 

Q: What is considered an intelligent fire system?

A: It is a system comprising, among other things:

 

• A central control panel that can be intelligent

• Intelligent addressable modules

• Detectors (smoke, thermal, optical, laser, among others)

• Manual stations

• Audible alarms

• Visible alarms

• Backup batteries

• Power supplies

• Conduit (conduit and wiring)

 

Smart systems are more reliable and accurate in identifying false alarms, as they are not usually triggered by environmental factors, vapors, dust, or kitchen smoke, as conventional systems are.

 

Q: What types of systems are used in industrial environments with flammable liquids?

A: To find the ideal solution for protecting industrial environments with flammable liquids, it's essential to maintain a list of all flammable liquids stored there, along with their respective safety data sheets. Safety data sheets are important because they specify the ideal fire mitigation measures for each product.

Based on what was said, flammable chemicals are generally not miscible with water and due to this detail the most commonly used solution is a wet water-foam sprinkler system, which must be designed according to many standards, such as NFPA 11, NFPA 13, NFPA 16, NFPA 31 or their equivalents in the Factory Mutual data sheets.

Another agent that can be used to extinguish this type of fire is carbon dioxide. However, the room or enclosure must be airtight so that, in the event of a discharge, the CO2 cannot escape and maintains an adequate concentration to displace oxygen and extinguish any fire.

There are other solutions, such as the use of dry chemical powder (DCP), but these are less common.