Smoke Control and Ventilation in Warehouses
When fires develop in warehouses, the amount of damage that occurs in the aftermath can result in thousands of dollars in repairs. A smoke clearance and control system can help you substantially reduce the amount of damage that’s done to stock and buildings. Occupants are given a simple escape path, which allows them to exit the structure quickly and safely.
With the right system in place, firefighters are able to get into the building and mitigate the fire at its primary source, which should reduce the amount of damage that occurs. Each year, there are upwards of 1,450 warehouse fires in the U.S. alone, many of which lead to fatalities.
By investing in smoke control and ventilation for your warehouse, you’ll be making a long-term investment that allows you to protect your warehouse and all of the items in it. In this guide, you’ll learn more about the various components that are necessary to implement a smoke control and ventilation system in your warehouse.
What Are Smoke Control Systems?
A smoke control system is designed to limit the spread of smoke while also delivering a method for extracting heat and smoke from a building. A properly designed smoke control system must meet certain smoke-free escape conditions that allow the building to be fully evacuated with only a small risk of injury, smoke inhalation, or death.
Why Are Smoke Control Systems Important?
Smoke control systems are important because they provide an easy route of escape, reduce the likelihood that damage will occur, and provide firefighters with the ability to more effectively combat the fire. These systems also facilitate higher travel distances to exits without needing compartmentation.
Legislation and Standards
Over the years, there have been numerous legislation standards pertaining to smoke control and ventilation in general buildings and warehouses, the primary of which include:
- NFPA 92 – This section of the National Fire Protection Association code provides requirements for designing a smoke control system
- NFPA 101 – This section of the NFPA code requires that smoke control systems maintain a smoke level that’s at least six feet higher than the highest seating level
- California Building Code 408.9.1 – In this portion of the California Building Code, all regulations for smoke venting are outlined
Nearly every building that a business operates out of is required to adhere to smoke control standards. These structures include industrial, commercial, and public buildings.
Industrial buildings are structures where materials or products are assembled, processed, or fabricated. The main types of industrial facilities include laboratories, assembly plants, warehouses, and fabricating plants.
In these facilities, smoke control systems are necessary because companies are unable to afford stopping production lines for lengthy periods of time. Even a single day of downtime can result in millions of dollars of lost revenue. When installed in an industrial facility, smoke control systems are designed to put out fires and get rid of smoke as quickly as possible with minimal clean up requirements.
Commercial buildings involve any building where commercial activities occur, the primary of which include retail spaces and office buildings. Many commercial buildings are protected with these systems. Since a large number of customers can be in a store or commercial building at a given time, it’s essential that they are able to escape from the premises safely. Allowance must also be made for families with children, disabled individuals, and elderly individuals.
A public building is any type of building that houses the local, state, or federal government and is open to the public. Many of the requirements that are maintained in commercial buildings must also be maintained in public buildings.
Any natural smoke control systems that are installed in a public building can be used to deliver natural ventilation, which will reduce internal temperatures when the weather is hot while also lowering the cooling loads. Natural ventilators are available with the inclusion of translucent flaps that accommodate daylight entry for the building in question.
Combating Fire and Smoke
Combating fire and smoke in warehouses is a three-step process that involves taking action during the early stages of the fire, understanding the smoke characteristics, and smoke logging.
Step 1. Early Stages of Fire
When a fire begins in a warehouse or other large building, it doesn’t spread like a fire in a home. When a fire begins at home, it’s likely that all of the windows and doors would be closed at the time, which results in the fire being suffocated and growth being significantly slowed.
Large industrial buildings contain a considerable amount of oxygen, which means that any fire in the building has optimal conditions for growing and spreading. In the initial stages, smoke that emanates from the fire will rise quickly to the roof area.
Step 2. Smoke Characteristics
Smoke is able to spread laterally at a high velocity of around five meters per second. Keep in mind that the average walking speed for a person is one-to-two meters per second. Once a building’s roof space is full of smoke, the smoke begins to build downwards. The geometry of the structure and nature of any combustibles in the building dictate how quickly smoke builds up.
Step 3. Smoke Logging
If a building isn’t properly ventilated, it could become smoke logged in several minutes. While this smoke will primarily consist of entrained air, it’s also possible for a substantial amount of asphyxiates and toxic substances to be present in the smoke as well. In this scenario, the smoke could disorientate an individual within seconds. This same individual could die in a matter of minutes.
Basic Smoke Control System Design
The purpose of a smoke control system is to reduce the spread of smoke and make it possible for heat and smoke to be extracted from the building. The three basic components of a smoke control system design include:
- Barriers that keep smoke from spreading throughout the building
- Fans or openings at a high level to make sure that smoke exhausts from the building
- Inlet ventilators that offer a replacement air supply in order to balance the amount of smoke that’s being extracted
The smoke reservoir consists of components like:
- Smoke curtains – These curtains can be either fixed or automatic drop curtains that help contain smoke.
- Movable curtain – This type of curtain comes with heat-resistant fabric and is typically placed at the ceiling level. The curtain will unroll and drop to a specific height in the event of a fire.
- Mezzanine floors – This floor can change the characteristic of the fire since any fire below the floor is converted from free burning to a compartment fire.
Extract ventilation involves such components as:
- Natural smoke ventilators – These ventilators provide day-to-day ventilation and are usually placed on the roof to accommodate heat and smoke extraction. They can also be used for fresh air inlet. When fires grow larger than expected, the smoke is hotter and more buoyant, which causes the ventilators to be more efficient.
- Mechanical smoke ventilators – This form of ventilation requires reliable power supplies. These systems are made to extract a certain volume of smoke no matter the fire size, which isn’t the case with natural smoke ventilators. An air inlet system is required.
- Mechanical extract systems – These systems come in many fan sizes and can be paired with OPV control systems.
- Natural ventilator – This is a type of flap ventilator that can be made with glass, translucent polycarbonate, or aluminum. It can be fixed horizontally or at an angle.
Inlet ventilation systems consist of an inlet and ventilators. Inlet air is necessary for smoke ventilation systems to work as intended. The inlet air supply provides a chimney effect that allows for consistent air flow into the building. When air and gas are removed by extract ventilators, they will be replaced with clean air through the inlet ventilators.
As for natural inlet ventilators, they should be positioned as low as possible in a building. You can provide inlet air with adjacent non-fire zones or automatic opening ventilators. The inlet velocity needs to be less than five meters per second.
High-bay warehouses consist of:
- High-bay storage areas – Fire in a warehouse tends to travel vertically, which is why sprinklers are essential to combat the spread of fire. Smoke control systems work together with sprinklers to get rid of the smoke.
- In-rack sprinklers and smoke vents – The majority of high-bay warehouses consist of in-rack sprinkler systems that mitigate the fire growth.
- Additional considerations – Think about the nature of goods that are stored, the type of packaging you’re using, the material’s surface area, the type of sprinkler system, and the manner of storage.
This aspect of a smoke control system involves:
- Fire compartmentation – Fire compartmentation curtains descend in your warehouse when a signal is sent to an alarm panel. Once the fire is mitigated, the curtain will immediately retract. These curtains are often placed near entrances.
- Fire curtain – These curtains seal off areas in a warehouse to contain a fire and keep it from spreading to other areas.
- Controls – A control panel can be used to operate numerous curtains. These panels typically come with a battery backup
OPV Control Systems
OPV control systems are electronic control systems that allow you to integrate various types of equipment into the smoke control system. The main benefits and features of an OPV control system include:
- Proven performance
- Conforms to modern standards
- Complies with the low voltage directive
- Complete control over how the panel operates
- Software for monitoring and diagnostics is included
- Low maintenance and power requirements
Sprinklers are comprised of the main sprinkler system and integration with vents. The majority of sprinkler systems aren’t capable of extinguishing fires completely. Instead, they are meant to control them. Keep in mind that sprinkler systems can expedite smoke logging issues.
As for the interaction of sprinklers with vents, it was once believed that removing heat through smoke vents could create delays with the operation of sprinkler heads. However, the presence of ventilation barely impacts the performance of sprinkler systems.
Why Choose QMH?
At QMH, we strive to always meet the warehousing needs that each of our clients have. We deliver end-to-end solutions, which is why we understand how to install and maintain a wide range of warehouse solutions. If you want to be certain that your smoke control system is functioning correctly and includes all of the latest technology, our team at QMH can answer any inquiries you have.