Exit Route as on OSHA

OSHA’s Means of Egress Requirements, 1910 Subpart E

Do your employees know how to escape in an emergency? Do you have enough exits for prompt evacuation? Have your exit routes, discharges and accesses been properly designed and constructed?

The Occupational Safety and Health Administration’s (OSHA’s) emergency evacuation requirements are contained under Subpart E of the General Industry Standards, 29 Code of Federal Regulation (CFR) Part 1910.

Under the umbrella of Subpart E, employers will find OSHA’s requirements for exit routes, as well as their standards for both emergency action and fire prevention plans. In addition to OSHA’s emergency egress requirements, employers must be cognizant of the emergency egress requirements of their local fire department. Local fire departments and Fire Marshals will typically be enforcing the emergency evacuation requirements of the National Fire Protection Association (NFPA). The local Fire Marshal or fire department inspector is considered to be the local Authority Having Jurisdiction (AHJ). And as noted below, OSHA recognizes compliance with the NFPA’s egress guidelines as meeting OSHA’s standards.

OSHA breaks down their exit route requirements within Subpart E as follows:

• Compliance with Alternate Exit-Route Codes (1910.35),
• Design and Construction Requirements for Exit Routes (1910.36), and
• Maintenance, Safeguards, and Operational Features for Exit Routes (1910.37).

In addition, under 1910.34, OSHA provides definitions related to egress. It’s here that the scope of the Subpart E is called out under 1910.34(a), where it states that every employer within general industry is covered by the requirements, with the exception of mobile workplaces such as vehicles or vessels.

Alternate Exit-Route Codes

OSHA recognizes some employers may be following the emergency evacuation requirements of other regulatory agencies. It acknowledges and accepts this under 1910.35 where it states, “OSHA will deem an employer demonstrating compliance with the exit-route provisions of NFPA 101, Life Safety Code, 2009 edition, or the exit-route provisions of the International Fire Code, 2009 edition, to be in compliance with the corresponding requirements in 1910.34, 1910.36, and 1910.37.” Both the NFPA 101: Life Safety Code® and the International Fire Code were last updated in 2015.

Design and Construction Requirements for Exit Routes, 1910.36

A couple key definitions are important to understand prior to reviewing OSHA’s emergency egress design and construction requirements. These definitions are found in 1910.34:

• Exit – means that portion of an exit route that is generally separated from other areas to provide a protected way of travel to the exit discharge. An example of an exit is a two-hour fire resistance-rated enclosed stairway that leads from the fifth floor of an office building to the outside of the building.
• Exit Access – means that portion of an exit route that leads to an exit. An example of an exit access is a corridor on the fifth floor of an office building that leads to a two-hour fire resistance- rated enclosed stairway (the Exit).
• Exit Discharge – means the part of the exit route that leads directly outside or to a street, walkway, refuge area, public way, or open space with access to the outside. An example of an exit discharge is a door at the bottom of a two-hour fire resistance-rated enclosed stairway that discharges to a place of safety outside the building.
• Exit Route – means a continuous and unobstructed path of exit travel from any point within a workplace to a place of safety (including refuge areas). An exit route consists of three parts: The exit access; the exit; and, the exit discharge. (An exit route includes all vertical and horizontal areas along the route.)
• High Hazard Area – means an area inside a workplace in which operations include high hazard materials, processes, or contents.
• Occupant Load – means the total number of persons that may occupy a workplace or portion of a workplace at any one time. The occupant load of a workplace is calculated by dividing the gross floor area of the workplace or portion of the workplace by the occupant load factor for that particular type of workplace occupancy. Information regarding the "Occupant load" is located in NFPA 101-2015, Life Safety Code, and in IFC-2015, International Fire Code.

Under 1910.36, OSHA covers the basic design and construction requirements for exit routes and offers additional details in the following areas:

• Number of exit routes needed
• Exit discharge requirements
• Locking considerations for exit doors
• Design requirements for exit doors
• Capacity and size requirements for exit routes
• Considerations for outdoor exit routes

Exit routes must be a permanent part of the workplace and exits themselves must be separated by fire resistant materials. In facilities where an exit connects three or fewer stories, the materials used to construct the exit must have a one-hour fire-resistance rating; for four or more stories a two-hour fire- resistance rating is required for exit construction materials.

In addition, openings to an exit are limited to only those from occupied areas of the workplace or into the exit discharge. All openings into an exit must be protected by a self-closing approved fire door that remains closed or automatically closes in an emergency. The fire door, frame and hardware must be listed or approved by a nationally recognized testing laboratory.

At least two exit routes must be available unless the number of employees, size of the building, its occupancy or the arrangement of the workplace is such that all employees would be able to evacuate using a single exit route. Where more than one exit route is present in a workplace, they must be located as far away from each other as possible to prevent all egress routes from being blocked by smoke or fire during an emergency. More than two exit routes must be available if the number of employees, the size of the building, its occupancy, or the arrangement of the workplace is such that all employees would not be able to safely evacuate during an emergency.

As noted in the definition above, the exit discharge must lead to a space with access to the outside. It must also be large enough to accommodate the anticipated number of building occupants likely to use it. And if it contains stairs that continue beyond the level at which the exit discharge is located, it must contain a door, partition or some other effective means to clearly indicate direction of travel leading to the exit discharge.

An exit route door cannot be controlled by any mechanical device that could fail causing the door to lock. Employees must be able to open the exit route door from the inside at all times without the use of keys, tools or special knowledge. The only exception to this would be exit route doors in correctional or mental health facilities. In those types of high security settings, supervisory personnel must be on duty at all times to ensure the facilities emergency egress plan can be safely implemented should the need arise.

In addition, exit route doors must be side-hinged. And if the room that the exit door is servicing is designed to be occupied by more than 50 people or is considered a high hazard area, the side-hinged door must swing out in the direction of egress travel.

Exit routes must support the maximum permitted occupant load for each floor served and the capacity of the exit route cannot decrease in the direction of travel toward the exit discharge. The ceiling of an exit route must be at least seven feet six inches high with any projection down from the ceiling not reaching less than six feet eight inches from the floor.

An exit access must be at least 28 inches wide at all points. And where there is only one exit access leading to an exit or exit discharge, the width of the exit and exit discharge must be at least equal to the width of the exit access. The width of an exit route must be sufficient to accommodate the maximum load capacity of each floor served by the route. Objects that project in must not reduce the width of the exit route to less than the minimum width required for the exit routes.

If an outdoor exit route is used, it must:

• Have guardrails to protect unenclosed sides if a fall hazard exits;
• Have a covering if snow or ice is likely to accumulate along the exit route;
• Have a reasonably straight design with smooth, solid and level walkways, and
• Not have a dead-end longer than 20 feet.

Maintenance, Safeguards, and Operational Features for Exit Routes 1910.37

During new construction, as well as facility repairs and alterations, employees cannot occupy a workplace until exit routes are in place and accessible. And during construction, repairs or alterations, employees must not be exposed to the hazards of flammable or explosive substances or equipment that are beyond the normal permissible conditions in the workplace, or that would impede egress.

Exit routes must be arranged so that employees will not have to travel toward a high hazard area, unless the path of travel is protected from the area by partitions or physical barriers. The exit routes must be free and unobstructed, and if they’re not “substantially level” (1910.37(a)(3)) stairs or a ramp must be provided. Also, exit routes must be kept free of explosive or highly flammable furnishings and the safeguards designed to protect employees during an emergency, such as sprinkler systems, alarm systems, fire doors, exit lighting etc., must be in proper working order at all times.

Exit access cannot go through a room that can be locked to reach the exit or exit discharge, nor can exit access lead into a dead-end corridor.

Proper lighting and marking of the exit routes are vital. Each exit route must be adequately lighted so that an employee with normal vision can see along the exit route, and each exit must be clearly marked by a sign that reads “Exit.” Each exit route door must be free of decorations or signs that can obscure the visibility of the exit route door.

If the direction of travel to the exit is not immediately apparent, signs must be posted along the exit access indicating the direction of travel to the nearest exit and exit discharge. Additionally, the line-of- sight to an exit sign must be clearly visible at all times. Should there be a doorway or passage along the exit access that could be mistaken for an exit, it must be marked as “Not an Exit,” or be identified by a sign indicating its actual use.

Exit sign requirements are detailed in 1910.37(b) (6) and 1910.37(b) (7). OSHA does not specify a mandatory color for exit signs. What they do state is:

• Each exit sign must be illuminated to a surface value of at least five foot-candles (54Lux) by a reliable light source and distinctive in color. Self-luminous or electroluminescent signs that have a minimum luminance surface value of at least .06 footlamberts (0.21 candela/square meter (cd/m2)) are permitted.
• Each exit sign must have the word “Exit” in plainly legible letter not less than six inches (15.2 centimeters (cm)) high, with the principal strokes of the letters in the word “Exit” not less than three-fourths of an inch (1.9 cm) wide.

If there are flame retardant paints or solutions used along the exit routes, they must be reapplied as necessary to maintain their fire retardant nature.

Emergency Action Plans and Fire Prevention Plans 1910.38 & 1910.39

As indicated above, 1910 Subpart E also covers the employer’s requirements for both emergency action and fire prevention plans. For those employers who are uncertain whether they need an emergency action plan, OSHA’s created an easy to use and interactive eTool. Among the resources in The Evacuation Plans and Procedures eTool, is an “Expert Systems” tab. This tab includes a series of questions that allow employers to determine whether their facility requires an emergency action plan.

Commonly Asked Questions

Q.		Is there a requirement for exit sign color? Some facilities have Green, other facilities have Red.
A.		There is no OSHA requirement for specific colors, however, OSHA states it must be distinctive in color from the background. NFPA 101 Section 7.10.1.8 states "Every sign required in Section 7.10 shall be located and of such size, distinctive color, and design that it is readily visible and shall provide contrast with decorations, interior finish, or other signs." Some states or local jurisdictions may require a certain color. Always best to check with your local AHJ.
Q.		When is a "No Exit” sign required?
A.		Under 1910.37(b) (5), OSHA states, “Each doorway or passage along an exit access that could be mistaken for an exit must be marked “Not an Exit” or similar designation, or be identified by a sign indicating its actual uses (e.g. closet).” The NFPA does specifically reference the "No Exit" verbiage under NFPA 101 Section 7.10.8.3.1. They state "NO EXIT" sign is needed where, "any door, passage, or stairway that is neither an exit nor a way of exit access and that is located or arranged so that it is likely to be mistaken for an exit.”

About LSZH Cable

Halogen-Free Cable

Increasingly used in public and government buildings and where there is sensitive electronic equipment (i.e. Hospitals, Supermarkets, Airports, Control Rooms & Computer Suites) these cables are designed for increased safety in the case of a fire:

•         Reduction in hazardous fumes which can cause injury when inhaled
•        Reduction in corrosive chemicals which can cause damage to electronics

Historically, most cables used in installations have been insulated with PVC or similar materials.  In fires, these insulation materials release chlorine gas.  Chlorine is a poisonous gas and a danger to people.  In addition it forms hydrochloric acid when coming into contact with water.   Hydrochloric acid (HCL) can have devastating effects on adjacent equipment.

To overcome the problems associated with the release of chlorine gas, halogen-free cables are used.  Typically a halogen free cable is made of polypropylene, which does not produce a dangerous gas or acid in fire conditions.

What are halogens?

Halogens are non-metallic elements found in the periodic table. The five halogens are fluorine, chlorine, bromine, iodine, & astatine. A common material that contains halogens in the chemical structure is PVC. Halogens make cable jackets and insulation highly flame retardant. Some naturally non-halogenated materials have halogen added because of the flame retardant properties. When burned, halogens emit a thick toxic smoke and become corrosive. These characteristics can cause damage to equipment and pose a safety concern.

Why consider halogen-free cable?

Over the last few years, halogen-free wire and cabling products have seen an increase in popularity. Halogen-free cables are used in consideration of issues including fire safety, fire damage prevention, and the environment. Halogen-free cables help eliminate the use of environmentally sensitive materials.

What does LSZH mean?

LSZH stands for low smoke zero halogen. The compounds in the cable insulation and jacket have no fluorine, chlorine, bromine, iodine, or astatine. This means that the cable emits little to no toxic halogens and minimal smoke when in contact with fire. These are important safety precautions and they often appear together in wire and cable specifications. LSZH wire and cable is also called: low smoke non halogen (LSNH), low smoke halogen free (LSHF), and low smoke zero (0) halogen (LS0H).

In what applications can halogen-free cable be used?

Halogen-free cable is intended for use in applications in which insulation with low toxicity, low smoke generation, and low corrosiveness is needed. Examples include rapid transit, industrial, shipboard, and commercial fields where human safety and protection of equipment is a concern.

Does the NEC allow low-smoke halogen-free cable in all applications?

The NEC (National Electrical Code) doesn't prohibit halogen-free cable or wire installation in any application. The NEC does require low smoke cables for plenum spaces.

Is there a difference between low smoke and zero halogen?

Low smoke and zero halogen are not equivalent. Low smoke cable emits a thinner and clearer smoke when burning. This feature makes evacuation and firefighting efforts much easier and safer. A cable may be low smoke and still contain toxic halogens. Zero halogen means that the cable does not contain fluorine, chlorine, bromine, iodine or astatine. Zero halogen cable may still emit a thick smoke when burned. Both properties are not always needed for all cables. Check specifications to be sure that the cable meets both requirements if necessary for your application.

Are there any disadvantages to using low smoke zero halogen cables?

Low smoke zero halogen cables provide a lot of great safety advantages, but there is a bit of an electrical and mechanical trade-off. In order to be low smoke zero halogen, the cable jacket must incorporate a high percentage of filler material. This increase in filler material could make the jacket less chemical and water resistant and could provide poorer mechanical and electrical properties than a non-LSZH counterpart. LSZH jackets are also more likely to experience jacket cracking during installation, so special lubricants may be necessary to avoid damage. This is especially true in cold environments. Because of the limited flexibility of LSZH, it is not recommended in robotic or continuous flex applications. As a result, LSZH cable is commonly chosen for applications where fire safety is more of a concern than the cable’s specific electrical and mechanical properties. Advances in compound materials and processing have decreased some of these issues.

Can LSZH pass a flame test?

Yes. LSZH may pass a standard flame test. To determine how an LSZH cable will react in a fire, the following five criteria are considered:

·        How easily the cable will catch fire

·        How quickly the fire will spread along the cable

·        How much smoke is produced upon combustion

·        How toxic are the byproducts

·        How corrosive are the byproducts

Some test standards related to this type of cable are Plenum rated, LS rated, S1 rated, and ASTM D5424.

What should be considered when choosing LSZH?

When choosing LSZH products, factors such as the environment and price should be considered. An environmental factor such as the temperature of the installation could reduce the flexibility of the cable. Will the application be in an open area or confined? Will other flammable material be present? Low smoke zero halogen cable also tends to be higher in cost. Consult an expert from Allied Wire and Cable to find the best fit for your application.

Cables intended to fulfil this type of function are often labelled as one of the following:

LSZH - Low Smoke Zero Halogen

LSOH - Low Smoke Zero Halogen

LSF - Low Smoke and Fume

OHLS - Zero Halogen Low Smoke

Both LSZH and LSF are used to limit smoke, fumes and halogen given off in fire conditions.

Halogen & Smoke Emission, Corrosively & Toxicity Standards

IEC 60754-1 / BS6425-1 - emission of halogen

IEC 60754-2 - corrosivity

IEC 61034-1 / ASTM E662 - emission of smoke

ISO4589-2 / BS2863 - oxygen index LOI

ISO4589-3 / BS2782.1 - temperature index TI

Fire Extinguishers Key Points

Fire Extinguishers Manufacturers Bring Key Points To Remember For Businesses

Fire extinguishing equipment’s range is vast and every product is intended with single objective- to combat fire when needed. Manufacturers of fire extinguishers today explain key points that one should consider while installing or even planning for installing firefighting equipment’s to their premises and building. These are significant facts that one should remember every time while shopping or installing any fire extinguishing equipment into home or office premises. 

1.  Manufacturers producing distinct types of fire extinguishers 

Every fire extinguisher is intended with single objective, i.e. to fight against fire. Manufacturers are designing each type of extinguisher for different fires. It is crucial to ensure fire extinguisher types that you are going to use in your building. These products should be of right type and have potential to combat fire. 

2.  PASS is what you need to remember to use extinguisher 

PASS (Pull the pin, Aim low, Squeeze the lever, Sweep the nozzle) play vital role while using any extinguisher. Never forget this golden acronym as it will help you and guide you when you use fire extinguishing equipment. 

3.  Professional inspection 

Make sure you invite professionals from licensed fire protection company for authentic inspection. If you just make a call to any local center, you may be taking risk to your life and assets. So, never take the testing and inspection of fire fighting tools and equipments for granted. Contact experts who know how to inspect these equipments in best possible way to ensure safety of the public. 

4.  You must install them near exits 

By installing fire extinguishers near exits, you will get more safety while using it. In case of fire, when you use fire extinguisher hanging on the wall near to exit, you have a clear path to take stairs and get out of the building. Evacuating is the initial thing people do in case of fire mishap. 

5.  Train people so that they can easily use fire extinguishers

It is necessary to provide special training to people in order to make them eligible to use fire extinguishers. There are many fire extinguisher manufacturers offering free training sessions to their clients. People can purchase extinguishers from them and get trained from professionals. 

These are essential points to remember at any cost. When you forget any of these points, you may encounter some serious trouble- believe us, we don’t wish this for you!

Fire Detection for Large Spaces

Fire Detection for Large Spaces: Integrating Aspiration Smoke Detection

Modern structures are complex, which makes them difficult to protect against smoke and fire. Features like large atria, vast open areas, or high ceilings can make the use of traditional smoke and fire detection methods impractical, ineffective, and difficult to maintain and operate.

Large, open spaces are prone to high airflow and smoke stratification (caused by the high ceilings and/or dilution of the smoke), making it difficult for smoke to reach spot-type smoke detectors and for conventional detection devices to operate properly. Additionally, significant effort is required just to test and inspect these devices in such spaces, per code requirements.

In general, fire detection in large volume spaces directly relates to the size of potential fires within the space. Building contents such as furniture, large trash containers, or merchandise displays typically burn with enough energy to push smoke to significant heights. However, low energy fires with a small heat-release rate are subject to stratification and can be difficult for ceiling or near-ceiling mounted smoke detection devices to detect.

What is considered a large space?

Large spaces are those with ceiling or roof heights extending tens or even hundreds of feet above the floor. Some examples are:

·        Spaces containing atria, such as hotel lobbies and shopping centers

·        Warehouses and distribution centers

·        Record/archive storage facilities and automated storage and retrieval warehouses

·        Manufacturing plants, such as automobile assembly plants

·        Convention centers, theatres, auditoriums, stadiums, and indoor sports facilities

·        Cathedrals, churches, temples, and mosques

·        Aircraft hangars and other large storage and maintenance areas

·        Transportation terminals, such as airport terminals and train stations

Regarding fire protection, large spaces can be classified into two basic categories:

Category 1: Large volume spaces with fire-load contents, generally of limited height, located on the main floor or other floors open to the large volume. These spaces tend to have moderate to large occupant loads. Examples: atria areas, single-story manufacturing areas, heritage buildings, religious worship buildings, and airport terminals.

Category 2: Large volume spaces with stacks or piles of combustible contents, which may or may not be in storage racks. These contents occupy a significant portion of the volume and height of the space that is most often one story. These spaces tend to have low to moderate occupant loads and a high value of contents. Examples: warehouses, distribution centers, automated storage and retrieval facilities, and library stack rooms.

Detecting Smoke in Category 1: Hotel

Atria, a popular architectural design feature, enhance the perception of light and space within structures but can be dangerous for occupants in a fire. One fire design challenge is compensating for the fluctuation of solar radiation that enters through large expanses of glass, which can often generate thermal gradients within the space and result in a hot gas layer near the ceiling or roof. This can vary from day-to-day, depending on thermal load and operations of HVAC or natural ventilation systems.

The base of the atrium is especially vulnerable. A fire at this location could potentially fill the unenclosed shaft with smoke, allowing fire to spread rapidly and transport heat, smoke, and toxic gases from floor to floor. More importantly, traditional technologies take too long to detect smoke in these large areas because smoke may not be buoyant enough to penetrate the ceiling layer of stratified environments. Aspirating smoke detection systems, however, can be designed to avoid the issues posed for ceiling-mounted spot smoke detectors due to a solar-induced hot layer.

Detecting Smoke in Category 2: Warehouses

Category 2 spaces require additional considerations beyond those previously discussed. Modern warehouses and storage facilities often rely on automatic sprinkler systems for basic fire protection. However, the potential loss of key supply chain facilities, high value storage, and irreplaceable archived storage can warrant the installation of early warning smoke detection for staff intervention before sprinklers are needed.

Arson and electrical/mechanical systems account for a significant percentage of warehouse fires, but aspirating smoke detection can provide early indications of such events and allow for manual fire suppression or depowering of equipment. STRUCTURE FIRES IN U.S. WAREHOUSES by Richard Campbell, published in June 2013 by the National Fire Protection Association Fire Analysis and Research Division, says that during 2007-2011, an estimated average of 1,270 structure fires in warehouses were reported to U.S. fire departments each year, with associated annual losses of 4 civilian deaths, 23 civilian injuries, and $188 million in direct property damage. According to Campbell:

·        Nearly one-fifth of these fires were set intentionally

·        Electrical distribution or lighting equipment was involved in 13% of fires

·        Electrical failure or malfunction was the leading factor contributing to the ignition of warehouse fires, as well as in contributing to direct property damage and to civilian injuries, representing 19% of the total in each category

Integrating Aspiration Smoke Detection

There are five basic design options for integrating an aspirating smoke detection system in warehouse and storage buildings. Selecting a sampling pipe configuration is dependent upon the warehouse application and internal characteristics (such as presence of high-bay racking, mezzanines, and voids) as well as the facility’s operational objectives and smoke detection objectives (performance-related).

1.     Near Ceiling Detection – sampling pipes are located close to the ceiling only

2.     Below Ceiling Detection – sampling pipes above a ceiling use drop down pipes or capillary tubes with sampling holes

3.     High-Low Alternating Detection – sampling pipes are located on the ceiling with alternating sampling holes on the ceiling and drop-down pipes

4.     Multi-Level Detection – this detection method applies to warehouses comprising high bay storage racks and utilizes more than one ASD system for ceiling and intermediate level detection.

5.     In-Rack Detection – the sampling pipes run horizontally or vertically between back-to-back racks at various heights. Drop-down pipes from the ceiling can also be used for in-rack detection.

In addition to these generic warehouse scenarios, additional aspiration protection should be considered in the following situations:

·        Office and control area: for aesthetic reasons, sampling in these areas is usually conducted via capillary tubes fed through the ceiling from the main sampling pipes, which are located in the ceiling void.

·        Ceiling void: it is especially important to protect ceiling voids containing cabling and/or any other equipment, due to an increased risk of fire. The spacing of the ASD sampling holes is again determined using the grid method.

·        Lighting areas: The ASD sampling pipes should not be placed underneath or in close proximity (<3.3 ft (1 m)) to lighting fixtures, heaters, skylights, or other heat-emitting objects.

·        Loading bay: ASD sensitivity should be lowered to account for the truck exhaust fumes regularly present in the loading bay environment.

Installation Scenarios

NFPA 72 provisions on the spacing and location of smoke detectors states that, “The location and spacing of smoke detectors shall be based upon the anticipated smoke flows due to the plume and ceiling jet produced by the anticipated fire, as well as any pre-existing ambient airflows that could exist in the protected compartment.”

Aspirating systems can be mounted wherever it is most convenient – on walls, columns or rack frames – but it’s recommended to mount the units in close proximity. For example, these units can be located in the center of a warehouse with the pipe network extending outward, toward the walls. This configuration minimizes the distance between detectors and reduces wiring costs.

There are many options for warehouse detection, including:

High-low alternating detection: this option is comprised of ceiling sampling holes that alternate with drop down pipes. This method is used to penetrate the hot air layer that may develop at the roof level, which allows for optimal sampling when the air at the roof level is either hot or cold. Consult local codes and standards to determine the correct length of drop down pipes for individual facility configurations [Figure 17].

In-rack detection: This may be used in warehouses with high-bay racking where stratification occurs, and/or localized detection is required. The air sampling pipe can have either a horizontal or vertical in-rack detection configuration [Figure 18]. Ideally, the detector is installed at the end of the rack at an accessible level. As a safeguard against mechanical damage from forklift trucks, sampling pipes should be located between back-to-back racks out of harm’s way.

Non-high-bay racking detection: In this case, ceiling drop-down pipes may also be used for in-rack detection. When installing drop-down pipes, here too, it is important to ensure that they will not be damaged by forklifts or be in close proximity to the stored goods. The drop-down pipes can be fitted to the sheltered side of the racking, fixed to the rack frame [Figure 19]. In-rack drop-down pipes normally have two or three sampling holes drilled in them to provide sampling at different heights within the racking system.

Multi-level detection: Additionally, this option can be used in high bay storage racking areas with expected high stratification levels and/or mezzanines (catwalks) consisting of solid flooring that will impede/delay the rise of the smoke plume. This design option requires one ceiling aspirating system and multiple intermediate level aspirating systems [Figure 21].

Benefits of Aspirating Smoke Detection

There are many hidden benefits of integrating an aspirating smoke detection system into the fire detection system design for a large volume space. It’s often a challenge to handle diverse placement options in fire and life safety designs, but aspirating smoke detection technology is flexible. It can accommodate a variety of horizontal and vertical sampling point locations and/or capillary tubes – providing effective coverage while minimizing architectural and aesthetic impact. Aspiration smoke detection systems also allow for more specific levels of warnings and alarms to allow building staff to investigate before emergency operations (such as evacuation) are implemented.

Aspirating smoke detection systems can also provide maintenance flexibility and cost savings for large spaces. Inspection and testing is easy, because an air sampling pipe network can be in the upper elevations of large volume spaces while the air sampling detector is installed in a remote accessible location. By comparison, spot-type smoke detectors located on high ceilings would require special procedures for inspection. Furthermore, aspirating technology performance is more consistent and reliable because it is not subject to building movement considerations of optical beam smoke detection devices.

Smoke detection Aspirating systems generally include a sensor of considerably increased level of sensitivity compared with a standard point or line optical beam detectors. Such “high sensitivity” aspirating smoke detection systems, are designated Class A systems in BS EN 54-20 and are often used to protect critical electronic equipment rooms, in which even a very small fire can result in unacceptable damage. Guidance on fire protection of such facilities is given in BS 6266.

Typically, a Class B (enhanced sensitivity) or Class C (normal sensitivity) aspirating smoke detection system is used in such applications, but it is important to seek advice from suppliers with sufficient experience and knowledge of aspirating smoke detection systems and BS EN 54-20.

For aspirating systems, specialist application guidance needs to be sought from the manufacturer.