Integrating fire protection & HVAC systems Tips

Top tips for integrating fire protection, HVAC systems

These nine guidelines will help fire protection engineers integrate fire and life safety systems with HVAC systems.

The fire and life safety systems within high-rise buildings, as defined by the 2012International Building Code (IBC) Section 403, serve to notify occupants of an emergency, suppress or control an active fire, evacuate or manage smoke in a fire area, and pressurize exit stairs for safe exit. The life safety systems often use HVAC fans and dampers to configure the required systems for a specific zone in alarm. Systems and components must be listed and approved for the purpose for which they are installed as indicated in 2012 IBC Section 907.1.3. 
There are many active and passive systems that provide life safety to occupants in high-rise buildings. Often they are integrated or work in unison to provide the safety intended. It is important to understand how they relate to each other in order to provide a proper approach to the design and installation of these systems.

Below are some important items to be considered when integrating fire and life safety systems with HVAC systems for both active smoke control and the recently introduced post-fire salvage, or smoke removal.

1. Prioritize control of any HVAC equipment used for smoke control so that the fire alarm control is the highest level of priority. This will override any other control signals to allow for the required airflow quantity for exhaust/makeup air, life safety damper closure and opening, and required unit shutdown. This may require bypassing hands-off automatic (HOA) or variable frequency drive (VFD) controls when life safety functions occur.

2. Each HVAC item that is required for smoke control or life safety systems (air handling unit smoke detectors, fire/smoke or smoke dampers, stair pressurization fans, smoke exhaust fans) may require a dedicated wiring connection to the fire alarm system. This is a parallel path from the HVAC control system if the fire alarm system is used for life safety control of the building management system (BMS). The BMS can monitor these connections, but no control can be given through the BMS unless the BMS is listed for smoke control. If the BMS is used for smoke control, and is listed, then the manner in which the fire alarm and BMS share signals needs to be incorporated into the design. 

3. Carefully review which type of activation is required for smoke control systems. Is it activated by the fire sprinkler system or the smoke detection system? For areas such as high-rise hotel tower corridors, a common method of activation is by smoke detection in the corridor. For low-rise podium smoke control zoning, a common method of activation is through fire sprinkler waterflow.

• If it is activated by fire sprinkler, then the sprinkler system zoning must match the smoke control zoning. Modifications to zone boundaries during construction will require modifications to sprinkler systems in the field.  
• If it is activated by smoke detector, then the detectors must be zoned to identify which units will activate the smoke control system and which will not.
• Some properties use both fire sprinkler and smoke detection to activate the same smoke control system. In these cases, both systems need to be coordinated with zone boundaries.

4. Coordinate zoning of HVAC equipment with the smoke control zoning. This will reduce the number of life safety dampers (smoke and combination fire/smoke) required in the system and allow proper unit shutdown and activation for a specific area without affecting other zones. Only a single zone in alarm will be affected for the active smoke control systems, but the fire alarm zone typically notifies both the area under emergency and adjacent spaces for evacuation and instruction. This is also important with fire/smoke dampers. Rather than splitting the branch ductwork within the adjacent zone, split the ductwork inside the zone to reduce the amount of fire/smoke dampers needed.

5. HVAC fans can be used for post-fire salvage duty (smoke removal) provided they are equipped with the proper accessories for a given jurisdiction. The 2012 IBC lists the base requirements for post-fire salvage systems in Section 403.4.7. For Southern Nevada, for example, amendments have been added to the code to further define the equipment requirements. These include an approved secondary source of power in addition to normal power, additional fan belts, and service factor similar to active smoke control fans (IBC Section 909 compliant). Elevated operational temperature requirements are not typically necessary for post-fire salvage systems because the fans are operated after the emergency event where they exhaust cold smoke. The designer should verify that any local amendments to the smoke removal systems have not added any requirements for equipment. 

6. For smoke removal systems, dedicated fire alarm connections to the associated purge fans are not required. This control can be completed by a signal from the post-fire salvage panel (either integral to the main active smoke graphics panel or separate) to the BMS to implement the type of control that is required to achieve the 15-minute air change for both exhaust and makeup air.

7. The design should consider the benefits of using either dedicated equipment or nondedicated equipment (HVAC fans). Dedicated fans are those used only for smoke control purposes and do not operate under normal HVAC conditions. They are typically used for stairwell pressurization and smoke exhaust systems. Because they are not used frequently they do not require as much maintenance, but they do require more frequent testing. Nondedicated fans (HVAC dual-purpose fans) are allowed by code and can provide benefit to smoke control systems to reduce costs. They are used for normal HVAC and smoke control and can be beneficial because they are maintained more frequently. However, maintenance needs to be performed such that it does not impact the smoke control operation. This includes any changes to VFD controls. The expected temperature of smoke must also be taken into account when selecting the temperature rating for active smoke control equipment (through either UL 705 Power Ventilator listed smoke exhaust fans or by providing calculations to clarify a reduced temperature rating, which may be 200 to 250 F for air handling unit fans).

8. The International Building Code requires ductwork that penetrates fire-resistance rated walls to be protected with fire dampers, smoke dampers, or combination fire/smoke dampers. Fire dampers are less expensive to install and maintain because they do not require power and smoke detection for control. Often fire/smoke dampers are the default because it is sometimes difficult to determine what type of wall is being penetrated. The design of the system needs to take into account the type of wall and the required damper to minimize costs, both upfront and ongoing, as well as reduce the complexity of the system. The layout of the ductwork also needs to be considered to minimize the amount of dampers. It is better to make one penetration into a corridor and feed the corridor with one duct than to penetrate with several lateral branch ducts, which require more dampers. 

9. VFDs are a great way to control the amount of air required under both HVAC and smoke control functions. Most VFDs are programmable to allow setpoints to be used for smoke control functions. The VFDs need to be designed and installed such that the setpoints established during smoke control testing are not changed in the field due to HVAC controls or other functions. It is important to recognize the relationship that the VFD plays in both smoke control and normal HVAC use. In addition, VFDs should be located in areas that provide a level of protection to the panel so that during a fire condition, they are not impacted by the fire. 

Employee Emergency & Fire Prevention Plans

Employee Emergency & Fire Prevention Plans

Employee Emergency Plans

Companies that fall under various OSHA standards such as 1910.120(l), hazardous waste operations and emergency response and 1910.119(n), process safety management of highly hazardous chemicals are required to have emergency evacuation plans that comply with 1910.38. Written employee emergency and fire prevention plans need to be kept by the employer in the workplace for companies with more than ten employees. Companies with ten or fewer employees may communicate the plans verbally. Employees should have access to these plans and should receive training related to emergency procedures. New employees should be informed of these plans during their orientation process. Current employees need to receive updates on plan revisions as they occur.

Employee emergency and fire prevention plans may vary to comply with specific company operation, but should follow the guidelines set by OSHA. Plans must include procedures for evacuating physically impaired workers. All employees must be familiar with the evacuation signal, whether it be communicated verbally or by bells, whistles or sirens. The alarm system must comply with scope, application, general requirements, installation and restoration, maintenance, testing and manual operation as stated in1910.165.

Emergency plans should include the following according to CFR 1910.38:

• ·       Emergency escape procedures and escape route assignments
• ·       Procedures to be followed by employees who remain to operate critical plan operations before they evacuate 
• ·       Procedures to account for all employees after emergency evacuations have been completed
• ·       Rescue and medical duties for those employees who are to perform them
• ·       The preferred means of reporting fires and other emergencies
• ·       Names or regular job titles of persons or department who can be contacted for further information or explanation of duties under the plan

Fire Prevention Plans

Employees should know the alarm procedure, where to find alarms and how to sound or activate them. Emergency phone numbers should be posted by phones. Employees should respond immediately when the alarm is sounded, whether it is a drill or an actual fire. Personal work areas should be secured, if time permits, by turning off machinery or equipment, securing hazardous materials or locking up confidential documents.

Evacuation routes must be indicated by signs or workplace maps outlining alternate escape routes. These must be posted in visible locations. A plan must include a designated area to meet for a head count immediately after evacuation.

According to CFR 1910.39, fire prevention plans should include the following:

• ·       A list of the major workplace hazards, their proper handling and storage procedures and potential ignition sources, including equipment/systems installed specifically to handle a fire involving them
• ·       Names/job titles of personnel responsible for maintenance of equipment and fire prevention and control devices installed within specific equipment
• ·       Names/job titles of personnel responsible for fuel source hazard control
• ·       A list of systems installed on heat-producing equipment to prevent accidental ignition of combustible material
• ·       Procedures to control accumulations of flammable and combustible waste materials.
•   E stablishing emergency plans and facilitating employee training help prevent fire deaths and injuries in the workplace. Saving lives is the goal for employee emergency and fire prevention plans. The plans only work if people know and follow the procedures.

Commonly Asked Questions

Q: Why is it important to meet for a head count in the event of an emergency or fire?

A: It is crucial to have a designated place to meet after the evacuation process. The head count helps to determine if anyone might possibly be trapped in the building. Failing to report to this designated meeting place could endanger the life of someone who re-enters the building in an attempt to find a missing person.

Q. Why is it important to keep exits clear?

A: It is important to keep paths, escape routes and aisles clear to ensure everyone can quickly exit the building. Clutter and debris might prohibit an exit door from opening to allow for escape.

Q. What is the evacuation plan?

Emergency evacuation is the immediate and urgent movement of people away from the threat or actual occurrence of a hazard. Examples range from the small scaleevacuation of a building due to a storm or fire to the large scale evacuation of a district because of a flood, bombardment or approaching weather system.

Q. What is a fire protection plan?

A Fire Protection Plan is a requirement needed for a building to obtain its Certificate of Occupancy (C of O). An FPP provides you with detailed floor plans of the building that shows all exits, doors, corridors and partitions serving as fire barriers.

Q. What is an emergency action plan?

An emergency action plan (EAP) is a written document required by particular OSHA standards [29 CFR 1910.38(a)]. The purpose of an EAP is to facilitate and organize employer and employee actions during workplace emergencies.

Changes to NFPA 13

13 Changes to NFPA 13

As the newest edition of NFPA 13 is set to be presented next month, NFPA has published some of the notable changes to this document:

1.               CPVC compatibility - where corrosion inhibitors are used in combination systems that include coated steel pipe and CPVC pipe, the coating must be tested for compatibility with CPVC.

2.               Freeze protection requirements - tentative interim amendments regarding antifreeze solution to prevent the freezing of water in sprinkler pipes has been formally adopted into the standard

3.               Sprinkler requirements for elevator spaces and hoistways - allows fire sprinklers to be omitted from elevator machine rooms, elevator machinery spaces, control spaces, or hoistways of traction elevators where a number of conditions are met, and brings the standard in alignment with other model building codes

4.               Title change to NFPA 13R - Standard for the Installation of Sprinkler Systems in Low-Rise Residential Occupancies

5.               Sprinkler protection in small bathrooms - Apartment buildings with bathrooms less than 55 square feet (5 square meters) must now have sprinkler protection where they were not  previously required to do so.

6.               Shadow areas -  shadow areas are permitted in the protection area of a sprinkler as long as they do not exceed 15 square feet per sprinkler.

7.              
"Sprinkler system" definition - modified to describe a system as an integrated network of piping that includes a water supply source, a water control valve, a water flow alarm, and a drain; this largely effects the requirements of NFPA 25.

8.               Backflow preventer requirements - a forward flow test will now be required on allNFPA 13/13R installations.

9.               Storage chapter - newly added; allows for an alternative design approach.

10.            Sloped ceilings - provides five common ceiling arrangements that allow for hydraulic calculations

11.            Water mist systems - refers users to NFPA 750.

12.            Cloud ceilings - protection to follow the use of obstruction rules.

13.            ESFR and CMSA sprinklers - these will now be permitted to protect light and ordinary hazard areas.

Coincidence Connection of Detectors for Triggering Extinguishing Systems

Guidance for Coincidence Connection of Detectors for Triggering Extinguishing Systems

This guide is a collation and explanation of the existing recommendations provided on the use of coincidence connected detectors with a particular focus on their application for triggering extinguishing systems. It defines a scheme for describing the different approaches to coincidence connection and in particular considers potential replacements for ionisation detectors.

Although predominantly aimed at assisting those involved in the automatic release of extinguishing systems, this FIA guide also provides information in situations where coincidence of detectors is needed for the actuation of other fire protection measures.

Review of Standards

There is a common misconception that BS 7273-1 Clause 5.2.3 calls for coincidence detection using two different types of detector, typically ionization and optical smoke detectors to trigger fire suppression systems. This is not correct.

5.2.3 Type of detector used

The selection of detectors should be in accordance with the recommendations given in BS 5839-1 and, where applicable, BS 6266. In some circumstances, fire detection considerations might dictate the need for use of two different principles of detection (e.g. optical smoke detectors and ionization chamber smoke detectors) to ensure the earliest warning of fire. In such circumstances, an even distribution of each type of detector should be provided throughout the protected space.

Where coincidence is used, normally it should be possible to achieve coincidence from two detectors of the same operating principle. In these cases, if, for example, two independent circuits are used to achieve coincidence, there should normally be an approximately equal number of detectors of each principle connected to each of the independent circuits. For example, where four detectors are required to protect the space and these comprise two optical smoke detectors and two ionization chamber smoke detectors; there should be one optical smoke detector and one ionization chamber smoke detector on each circuit.

However, it is not always necessary to use two different principles of fire detection. For example, given the type of fire anticipated and the speed of detection required, it might be acceptable to use detectors of a single type.

BS 7273-1 does not require the use of detectors using two different principles of operation:

·        Clause 5.2.2.1 suggests that co-incidence detection is one method of minimising the possibility of false discharge.

·        Clause 5.2.2.4 clarifies that co-incidence detection requires alarm signals from two independent detectors (whether the same type or not).

The second paragraph of clause 5.2.3 (above) was originally a continuation of paragraph 1 and as a separate paragraph is now confusing. The intent is to clarify that where mixed types are used, it is not normal to require both types (e.g. optical and ionisation) to have indicated an alarm before the extinguishant is released. In other words extinguishant may be triggered from any two independent detectors e.g. two ionisation detectors or two optical detectors or an ionisation and an optical detector.

Clause 5.2.3 only includes as examples the traditional combinations of optical and ionisation detectors. There are many other technologies which may be used, for example flame detection, multi-sensor devices, aspirating smoke detectors (ASD) which can be used to mitigate the risk of inadvertent discharge of extinguishant.

BS 7273-1 refers back to BS 5839-1 and BS 6266 for advice on the selection of fire detectors. Both these standards have been revised since BS 7273-1 was published and provide useful guidance:

·        BS 6266:2011 Clause 8.3

·        BS 5839-1:2013 Clause 21

Options for Coincidence Detection

Co-incidence detection is when at least two independent detectors are used to initiate the release of the extinguishing system. These can be of the same type or of two different types.

The type(s) chosen should be selected dependant on the fire risk and on the objectives of the fire system.

Given that ionisation smoke detection is in obsolescence, the traditional ionisation / optical combinations as exemplified in BS 7273-1 is losing relevance.

Some common possible alternative combinations include:

·        Optical & Optical

Traditional scatter type optical smoke detectors

o Optical smoke detectors must pass a range of fire tests including smouldering and flam-ing types and have proved to be suitable for many applications requiring co-incidence

o Flaming fires will be detected; however response may be slower than ionisation detec-tors

·        Optical & Optical-Heat (or Optical-Heat & Optical-Heat)

o Optical-Heat detectors speed the response of a standard optical smoke detector to a flaming fire by responding to heat

o Some Optical-Heat detectors may respond more slowly to a smouldering fire than a traditional optical detector

·        ASD & ASD (or ASD & other)

o  Very early warning of incipient fires is possible using Class A & B ASD systems which can

prompt early intervention and avoid automatic discharge of the fire suppression system

– whether to a real fire threat or an unwanted event (false alarm)

o    ASD & ASD requires two separate detectors to achieve true co-incidence detection

o    Inputs to the extinguishing system must be carefully selected (e.g. Class C only)

o    See also FIA Aspirating Smoke Detectors CoP

·        Optical & Flame (or Flame & Flame)

o    Fast detection of flaming fires

o     Flame detector requires unobstructed line of sight to area of coverage

o    Used only in special applications where flame is a particular risk

·        Multi-sensor & Multi-sensor (including dual-optical)

o   Many different types available with many different modes of operation therefore careful consideration needs to be made of the configuration of the detectors

o   Often designed to mitigate nuisance alarm risk and enhance fire detection

·        Heat & other

o   The use of heat detectors only is not recommended as heat detector response is very slow in comparison to a smoke detector

References and Applicable Standards

BS 5839-1:2013, Fire detection and fire alarm systems for buildings - Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises

BS 6266:2011, Fire protection for electronic equipment installations. Code of practice

BS 7273-1:2006, Code of practice for the operation of fire protection measures. Electrical actuation of gaseous total flooding extinguishing systems.

Fire alarm installation practices and workmanship

Fire alarm installation practices and workmanship

The nature and quality of the fire alarm installation work needs to be such as to maintain the integrity of the fire alarm system and minimize the duration and extent of disablement of the system during maintenance or modifications. Installation practices and workmanship need to conform to the requirements of BS 7671. 

Penetration of construction (e.g. for the passage of cables, conduit, trunking or tray) need to be “fire stopped” to avoid the free passage of fire or smoke, regardless of whether the construction has a recognized degree of fire resistance.

Recommendations:
The following recommendations are applicable.
1) The entire electrical fire alarm system installation should conform to the requirements of BS 7671. In general, the recommendations of this standard supplement, but do not conflict with, these requirements. Where any such conflict is considered to exist, the recommendations of this standard should take precedence.
2) Cables which are directly fixed to surfaces should be neatly run and securely fixed at suitable intervals, in accordance with the recommendations of the cable manufacturer. Cables should not rely on suspended ceilings for their support.
3) The installer should ensure that all wiring complies with, at least, 26.2f) to 26.2o).
d) Joints in fire alarm cables, other than those contained within the enclosures of equipment, should be avoided wherever practicable [see 26.2g)].
4) So far as is reasonably practicable, cable routes should be selected to follow the recommendations . Care should be taken to ensure the electrical continuity of electromagnetic screens, including metallic sheaths of cables.
5) Where new conduit, trunking or tray is installed, its capacity should be in accordance with the recommendations given in BS 7671.
6) Where a cable passes through an external wall, it should be contained in a smooth-bore sleeve of metal or other non-hygroscopic material sealed into the wall. This sleeve should slope downwards towards the outside and should be plugged with a suitable non-hardening waterproof compound to prevent the entry of rain, dust or vermin.
7) Where a fire alarm cable passes through an internal wall, a small clearance hole should be provided. If additional mechanical protection is necessary, a smooth-bore sleeve should be sealed into the wall.
8) Care should be taken to ensure that the ends of any sleeves are free from sharp edges which might damage cables during installation.
9) When a cable passes through a floor, the considerations a sleeve should extend as far above floor level as is required for protection of the cable it is to carry, but never less than 300 mm.
10) Where cables, conduits, trunking or tray pass through floors, walls, partitions or ceilings, the surrounding hole should be as small as reasonably practicable and made good with fire stopping materials that ensure that the fire resistance of the construction is not materially reduced. Spaces through which fire or smoke could spread should not be left around the cable, conduit, trunking or tray.
11) If cables or conduits are installed in channels, ducts, trunking or shafts that pass through floors, walls, partitions or ceilings, barriers with the appropriate level of fire resistance should be provided within the channels, etc. to prevent the spread of fire unless, in the case of ducts and shafts, the construction of the duct or shaft affords equivalent fire resistance to the structure penetrated; in the latter case fire stopping need only be provided where cables pass into, or out of, the duct or shaft.

L2 Fire Alarm

L2 Fire Alarm

IS 2189 : 2008: Indian Standard. Selection, Installation And. Maintenance Of Automatic Fire. Detection And Alarm System

IS 11360 (1985): Specification For Smoke Detectors For Use In Automatic Electrical Fire Alarm System [CED 22: Fire Fighting]

A fire alarm system is number of devices working together to detect and alert people through visual and audio appliances when smoke/fire is present. These alarms may be activated from Smoke Detectors, Heat Detectors, MCP etc.

Smoke detectors do not have a listed spacing. They have a recommended spacing of 30 feet between detectors. However, smoke detectors can be installed up to 41 feet apart in corridors up to 10 feet wide. The main fact to remember is that all points on the ceiling must be within 21 feet of the detector.

Commercial systems are categorized as follows (All include manual call points):

·         L1 – Detection provided throughout the entire premises

·         L3 – Detection provided on all escape routes and adjoining areas

·       L3/L2 – Detection provided on all escape routes and adjoining areas, as well as additional detection in specified high risk areas

·         L4 – Detection provided on all escape routes only

·      L4/L2 – Detection provided on all escape routes and additional detection in specified high risk areas

When a system is installed in a premises where there is more than one interlinked system in operation, then the suffix “X” is used.

Many fire authorities are now insisting on specific standards of fire alarm systems within buildings.  These categories are defined in the recommendations of BS5839.  One of the most common categories which is being asked for is a BS5839 category L2 Fire Alarm System.  The prefix 'L' for the category type stands for life protection.  This means that the primary purpose of a category L2 Fire Alarm is to protect life.  Whereas BS5839 system designs with a 'P' prefix are primarily designed to protect damage to property.

L2 Fire Alarm Systems are designed to offer automatic detection on all escape routes within a building, with the addition of all rooms adjoining to the escape route.  An L2 Fire Alarm design should also take into account any further areas of high risk which may not necessarily be covered with detection on the escape routes and adjoining rooms.  Examples of these areas could be boiler rooms, plant rooms and other areas with heavy plant machinery (such as in roof voids).

An Example of an L2 Fire Alarm Design

L2 Fire Alarm designs should also incorporate audible sounders throughout the building which operate when the fire alarm system is activated.  These sounders should achieve a minimum sound pressure of 65 dB (A) throughout the building and a minimum of 75 dB (A) at the bedhead where there people sleeping within the building.

An L2 Fire Alarm should also include manual call points on all exits to open air, and in buildings above a single storey all entrances to stairwells on the floors above the ground floor.  In large buildings it should also be noted that nobody should have to travel for more than 35 metres to reach a call point.  This means that further call points may be needed to be positioned within the property to achieve this.  Call points may also need to be positioned in high risk areas.  One example of this may be a paint booth where high flammable substances are present.  A call point may need to be positioned in close proximity to enable an alarm to be raised quicker should an incident occur.

Awareness of the system user is also essential, less able bodied people may or may not be capable of exiting without assistance, but high levels of people with sporting injuries or with hearing difficulties may require a system which addresses their needs.