Linear Heat Detection

Linear Heat Detection (LHD) is a versatile and economical fire detection product. Designed for use in a wide variety of fire and heat detection applications, LHD cable is particularly suited for harsh environmental conditions, where maintenance access is in a physical or hazardous area, and/or where there is a requirement to cost-effectively install fire detection in close proximity to the hazard. 

Linear Heat Detection cable is a combination of advanced polymer and digital technologies that can detect heat conditions anywhere along the length of the cable. The cable is comprised of two tri-metallic conductors individually insulated with a heat sensitive polymer outer-layer, and engineered to break down at specific fixed temperatures. This allows the twisted conductors to make contact and initiate a fire alarm condition at the control panel, without any calibration for changes in the ambient temperature. Nor is it required that a specific length be heated in order to initiate a fire alarm, adding to the versatility of this unique product. 

Alarm Point Location Setup

Each Protecto wire zone is field calibrated after installation to eliminate copper feed cable resistance from the Alarm Point Location reading. This is done by manually shorting the detector at the beginning of the zone and adjusting the display to zero "0000". 

Alarm Point Location Reading

When an overheat (alarm) occurs in a zone, an alarm point reading is taken either *manually or *automatically at the control panel. This reading represents the linear distance to the actuated point along the detectors length.

For further flexibility, Linear Heat Detection cable can be utilized with fire alarm control panels by utilizing either addressable monitor modules on an intelligent system, or by connecting the cable directly to the detection circuit of a conventional fire detection and control panel. In addition, the distance locating option allows the control panel to identify and display the exact location, in feet or meters from the fire panel, where the heat source interacted with the linear heat detection. That's a tremendous amount of valuable information in a small, easy to install and maintain fire detection package! 

·        Easy installation and maintenance

·        Minimal false alarms

·        Provides hazard coverage at every point on the cable for maximum protection

·        Compatible with intelligent and conventional detection and fire alarm panels

·        Available in a variety of lengths, cable coatings and alarm temperatures for maximum flexibility

Applications of LHS Cable

• Cable Trays
• Plant Rooms
• Vehicles
• Multi Storey Car Parks
• Thatched Roofs
• Industrial Kitchens
• Warehouses
• Waste Recycling Facilities
• Process Plants
• Hazardous Areas
• Power Stations
• Coal conveyors
• Cable Tunnels
• Access Tunnels
• Plant Rooms
• Shipping and Marine
• Engine Room
• Cable Ducts
• Ceiling Voids
• Kitchens

Common cause of fire in Hospitals

Common cause of fire in Hospitals

Fire safety in health care facilities—hospitals, nursing homes, clinics—presents a specialized response. Patients and families have trusted you with the safety of people who, in many cases, cannot help themselves.

Hospitals and Nursing Homes have certain special features which are not identical to other categories of Buildings. As per National Building Code (NBC) Hospital Buildings, Nursing Homes, categories under Group-C “Institutional Building”.

The Institutional Buildings are having some high risk areas with special problems relates life risk of both ambulatory and non-ambulatory patients. Life Safety from fire in Hospitals relies on a “Defined – in- Place” principle. Horizontal exits or smoke barriers are required to sub-divide each storey of a Hospital to provide an area of refuge on each floor.

Hazard Analysis:-

       A. Equipment’s Hazards

With the rapid technological advancement in medical science, hospitals and nursing homes are now equipped with a vast array of new equipment like.

Computerised Axial Topography scanners, Magnetic Resonance Imagers (MRI), lasers. Sophisticated Diagnostic and Treatment Equipment, Heaters, boiler etc.

B.     Chemical Hazards

1. Flamable chemicals

2.      Alcohols

3.      Solvents.

a.     Acids

b.     Ethers

c.      Sprits

3. Gas Stores

1. LPG Cylinders
2. Oxygen Cylinders
3. Nitrous Oxides etc.

4. Plants

1. Laundry & sterilization plants
2. A/C Plants & ducts
3. ‘X’ Ray suits

5. Kitchen & Canteen

6. General Store

7. Car park area

8. Mattresses, bedding, furniture, Oxygen cylinders, Pipe Line carrying Oxygen or Nitrous oxide in Patients’ rooms.

 

A number of different materials and types of equipment are major contributors to hospital fires.

Major incident in India:

A. December 2011: AMRI Hospital, Kolkata, WB, India—91 Fatalities dead

1. The fire in this private hospital started in the basement, where highly flammable medical equipment was illegally stored.

2. Hospital staff abandoned the hospital when the fire started and did not try to rescue any patients.

3. The fire service arrived 90 minutes after the start of the fire. Windows and doors were locked; windows had to be broken to gain access.

4. Most deaths were a result of smoke inhalation.

B. October 2016, twenty two patients died and many others were injured in a major fire accident at a private hospital in Bhubaneswar.

Fire and Safety Association of India (FSAI) Karnataka chapter, which conducted a survey, has found out that over 4,000 hospitals in Karnataka are not following the standard fire safety rule.

It was also found that some hospitals in Bangalore are not even using extinguishers properly. P Lakshminarayana, Bengaluru chapter of FSAI, said, “To our shock, we found some hospitals hiding the extinguishers. Reason? Since it was red in colour, it did not suit their interior design. We really don’t understand what is more important? Lives or design? Also, the emergency doors are always kept locked or there were hospitals which had kept their old documents and papers at the door making them inaccessible.”

The problem as identified in different hospitals in India are appended hereunder-

a)                External firefighting and rescue operation are very difficult.

b)                Evacuation takes unreasonable time.

c)                Simultaneous rescue and firefighting operation to be done mainly within the building.

d)          Building being fully air-conditioned, heat and smoke traps inside the building during fire.

e)                Smoke venting problems & Danger of flash over.

f)                Large number of occupants with unpredictable human behavior is in case of fire.

g)               Special care is required for non-ambulant patients.

h)               Special care is required to keep escape routes clear from smoke and heat.

i)           Hazards from increasing use of interior finish decoration and Compartmentation with combustible materials.

j)                 Multi occupancy hazards, high fire loads;

k)               Unserviceable water supplies;

l)                 Unserviceable fire protection systems and equipment

Fire from Electrical Equipment

Air Conditioners: “AHU/centralised AC units reported much fewer fires than split/window AC units”
Root Causes:
Ø Overuse, so the equipment heats up.- Domestic air conditioners are not meant for 24x7 operation.
Ø Not properly maintaining the AC units - A clean filter reduces fire risk as well.
Ø Poor electrical wiring - Provide industrial sockets and circuit breakers along with the right wire gauge.

Other Electrical Equipments and Switch Gears - ‘Switch gears, Light fittings, UPS systems, Laboratory equipments, Computers….’
Root Causes:
Ø Design issues / Equipment installation. - Mounting of distribution board/fuse box on wooden plank will not reduce electrocution risk but increase fire risk !
Ø Poor Maintenance - Major share of electrical mishaps happens during maintenance without work permits !
Ø Human Errors ‘ -Technical qualification, SOP, Training’

PREVENTION

The Fire Safety Audit Committee formed by the West Bengal Government in the wake of the devastating fire at AMRI Hospital in Dhakuria December 2011 has detected lapses in fire safeguards at almost all the establishment they have inspected, which has prompted the Government to come up with more stringent rules.

Minister for Fire and Emergency Services Javed Ahmed Khan said that the Government is going to mandate the appointment of a fire safety officer in all hospitals across the State.

1.      One of the primary considerations in preventing hospital fires is to prohibit the use of combustible structural (e.g., floors, walls, roofs, stairwells, fire escapes) and nonstructural (e.g., doors, windows, ceilings, fixtures, façade, insula­tion, mechanical and electrical conduits) components in the hospital facility.

2.      Materials used in the design and construction of hospitals must be noncombustible/nonflammable, must have ad­equate fire resistance ratings, and should not emit toxic gases/smoke during a fire. Fire resistance ratings are usually dependent on the layout, occupancy, and usage of the facility.

 Some examples of materials that emit toxic fumes during a fire and should be avoided are:

·        Polystyrene (for example, polystyrene decorative moldings)

·        Insulation spray foams, polyurethane and isocyanate foams

3.      ICUs and accident and emergency units should be located on the ground floor or first-floor level with dedicat­ed access ramps. Typically, high-traffic units (e.g., diagnostics) are located on the lower/ground floors. (Note: The configuration of an ICU ward is completely different from that of other wards.)

4.      The width of the corridor leading to the emergency exits (unobstructed) should be at least 2.4 m (7.9 feet). This will permit the transportation of hospital beds, mattresses, and so forth in the evacuation of non-ambulatory patients.

5.      Evacuation maps should be posted at the hospital’s main access points to clearly identify egress routes. It is important to note that the evacuation may not necessarily involve patients and personnel exiting the building; they may be required to move to an upper floor.

6.      Suggested requirements for installing and locating fire alarm–initiating devices are as follows:

·        The operable part of the Manual pull box should not be more than 1.07 m (42 inches) to 1.22 m (48 inches) above floor level.

·        Manual pull boxes should be located so that they are conspicuous, unobstructed, and accessible.

·        Manual pull boxes should be located so that the horizontal travel distance between boxes on any floor is not more than 61 m (200 feet).

·        Additionally, manual pull boxes should be located within 1.52 m (5 feet) of either side of a grouped opening

7.      The location of smoke and heat detectors depends on the type of detector being used and the geometry and occupancy of the space. Typically, the maximum coverage areas for smoke and heat detectors are 100 square meters (1,076.4 square feet) and 50 square meters (538.2 square feet), respectively.

8.      Regulations as per National Building Code 2005 : 

1. All high-rise buildings need to get NOC as per the zoning regulations of their jurisdiction concerned.
2. A road which abuts a high rise should be more than 12 metres wide, to facilitate free movement of Fire Services vehicles, specially the Hydraulic Platform and Turn Table Ladder.
3.Entrance width and clearance should not be less than 6 metres or 5 metres, respectively.
4. Atleast 40 per cent of the occupants should be trained in conducting proper evacuation, operation of systems and equipment and other fire safety provisions in the building, apart from having a designated fire officer at the helm.
5. The buildings should have open spaces, as per the Zonal Regulations.
6. Minimum of two staircases with one of them on the external walls of the building. They should be enclosed with smoke-stop-swing-doors of two-hour fire resistance on the exit to the lobby.

9.      Once a fire has been detected, a suppression system to extinguish the fire is required to minimize damage and avoid evacuation. A variety of firefighting equipment can be installed in different locations in the hospital to combat specif­ic types of fires, with special consideration to the patients occupying each area and the medical equipment housed in those areas.

10.   The rapid spread and accumulation of smoke usually poses one of the highest risks to human life in the event of a fire. One of the means of minimizing this danger is by incorporating special smoke extraction systems, usually in the initial design of heat, ventilation, and air-conditioning (HVAC) systems.

11.    One of the most critical aspects of planned preventative maintenance. Regular checks should be performed and documented as part of a health care facility’s management system. When an equipment item has been checked, it should be tagged and signed off for safe use with an indica­tion of any action taken and the next scheduled check date.

·        Fire Panel operate on batteries, smoke/Heat detectors, Manual Call/Pull Box, Notification Hooters should be checked as part of standard hospital mainte­nance, usually every month.

·        Water sprinkler systems require planned preventative maintenance as well as robust reactive maintenance procedures. Generally, individual sprinkler heads are virtually maintenance free; therefore, costs are related to maintaining the system through weekly tests and upkeep of water supplies and pump equipment.

·        Hose reels should be checked and signed off monthly.

·        All mechanical systems, including sprinkler systems, smoke extractor systems, and water storage tanks, need to be designed to resist earthquakes.

12.   General training of all staff should include, but not be limited to, the following:

·        Training on how to lift and move patients.

·        Training on how to use fire extinguishers.

·        Training on what to do if they see a fire. For example, the RACE acronym specifies actions to be taken in a fire (although not in a specific order; the hospital’s incident commander determines the appropriate actions to be taken in a given situation)

·        Training on what to do if they hear the alarm and see the flashing lights.

Hospital engineering service provision for Fire Protection according to NABH:
1. Fire fighting installation approval must be obtained
2. Location of control room should be easily accessible.
3. Control panel & manned, PA equipment should be connected with detection system or fire alarm system.
4. Pumps and pump room
5. 2 separate pumps i. e .Electric and diesel pump should be available
6. Provision of Forced ventilation should be there.
7. Arrangement of filling Fire tenders
8. 4 way fire inlet must be present in case of emergency
9. Proper access for Fire tender to fire tanks
10. Fire Drill should be performed
11. Yard Hydrants should be available
12. Ring main and yard hydrants should be as per strategic locations.
13. 2 way fire heads to charge the ring main
14. Landing Hydrant & Hose reels
15. Wet riser system must be installed
16. First aid Fire fighting appliances must be in working conditions
17. First aid equipment cabinets
18. Provision of Escape routes - escape stair
19. Sprinklers system - basement & bldg. above 15 M in height
20. Automatic Smoke detectors / heat detectors
21. Provision of Fire Alarm System & Fire extinguishers

Remember the RACE Against Fire

RESCUE any individual directly threatened by fire. Patient safety is the primary consideration, so move patients who are in immediate danger away from smoke and flames. Place the patient in a nearby room, behind a closed door.

ACTIVATE the alarm if you discover a fire or respond immediately to the alarm if you hear it sound.

CONFINE the fire by closing doors to slow the spread of smoke and flame. Close the doors of patients’ rooms. In general, residents are safer in a closed room than in a smoke-filled hallway.

EXTINGUISH the fire only if the fire is small, and if you know how to operate a fire extinguisher. Be sure the area has been cleared and the fire department called.

¨Some typical example discharge times are.
¨2 Kg CO2 10 seconds*
¨5 Kg CO2 20 seconds*
¨3 litre Water 10 seconds*
¨9 litre Water 55 seconds*
¨3 litre Foam 10 seconds*
¨9 litre Foam 40 seconds*
¨4kg Powder 11 seconds*
¨9kg Powder 18 seconds*
¨1kg Powder 7 seconds*

Fire detection and alarm systems for buildings

BS 5839-6:2013 Fire detection and alarm systems for buildings - Code of practice for the design, installation, commissioning and maintenance of fire detection and fire alarm systems in domestic premises

There have been many books published as detailed guides to BS 5839 and its many parts, some of which extend to more than 200 pages. In this document, we are focusing on clarifying some of the more popular issues and the questions which are commonly asked by designers, installers and maintenance personnel.

This document is intended as a guide to BS 5839: Pt.6: 2013. It is not a substitute for reading the Code of practice itself. Instead, it's designed to help make the implications and recommendations of BS 5839: Pt.6 more clearly understood, and to offer advice on how to design, install, commission and maintain a system that meets the requirements, with reference to the 2013 amendments.

BS 5839-6 is the key standard for fire detection in domestic premises. It is written to assist the non-specialist in compliance and will help make installations easier to audit. The standard is used by enforcing authorities and contractors, and applies to domestic premises accommodating single families, houses in multiple occupation (HMOs) and sheltered housing (housing and common areas). It applies both to new and existing housing.

The Document Itself

Each clause of the document is split into 2 parts. Firstly, there is the commentary - in italics - this sets out the reasoning behind the recommendations. The recommendations are written in upright (roman) type, so it is quite possible to simply refer to these alone. The intention of the commentary is to make the document easier to use; whether it succeeds in this aim is a matter of personal perception.

BS 5839: Pt.6 - An Introduction

BS 5839: Pt.6 is not intended for householders themselves, but to provide guidance and recommendations for architects and other building professionals, enforcing authorities, contractors and others responsible for implementing fire precautions in buildings. Householders should refer to the government guidelines.

The Code of Practice should not be quoted as if it was a specification and the standard itself warns that particular care should be taken to ensure that claims of compliance are not misleading.

It is also pointed out that compliance with a British Standard cannot automatically confer legal immunity. However, for a landlord or installer, compliance with the latest Code is obviously the best line of defence in any claim made against them.

The Scope of BS 5839: Pt. 6

This Code of Practice covers fire alarm systems starting from a simple self-contained battery smoke alarm right through to major systems with central panel(s) in accordance to BS 5839-pt1.

BS 5839: Pt.6 covers the following domestic building types:
Bungalows
Multi-storey houses
Individual flats
Individual maisonettes
Mobile homes
Individual sheltered accommodation as well as their common parts
Houses in multiple occupation (HMOs)
Certain NHS housing in the community
Mansions
Shared houses
Houses divided into several self-contained single-family dwelling units


Not included are hostels, caravans, boats (other than permanently moored) and communal parts of blocks or flats or maisonettes.

BS 5839: Pt.6 is primarily concerned with saving lives and reducing injuries. However, it does contain within it recommendations for helping to reduce property damage too. Good fire safety practice and adherence to the Code can give the best possible early warning of fire and so reduce the financial impact as well as human suffering.

The Grade System

Relates to system engineering, not level of protection.

BS 5839: Pt.6 grades fire detection systems from Grade F up to Grade A. Generally speaking, the greater the fire risk and the more demanding the application, the more comprehensive the system needs to be.

·       Grade F - System of one or more battery powered smoke alarms (and heat alarms if required)

·       Grade E - System of interlinked mains powered smoke alarms (and heat alarms if required) with NO stand-by supply. The interlink can be hardwired or radio-interlinked.

·       Grade D - System incorporating one or more interlinked mains powered smoke alarms (and heat alarms if required), each with an integral stand-by supply. The interlink can be hardwired or radio-interlinked.

·       Grade C - System consisting of fire detectors and alarm sounders (which may be smoke alarms) connected to a common power supply, comprising normal mains and stand-by supply, with central control equipment

·       Grade B - Fire detection and alarm system comprising fire detectors (other than smoke alarms), fire alarm sounders and control and indicating equipment to either BS EN 54-2 (and power supply to BS EN 54-4), or to Annex C of BS 5839: Pt.6

·       Grade A - Fire detection system incorporating control and indicating equipment to BS EN 54-2, and power supply to BS EN 54-4, installed to BS 5839: Pt.1 with some very minor exceptions

As the overwhelming number of residential applications in the UK will fall into the D to F categories, this is the area on which this guide will naturally focus. If you are particularly interested in unusual grades of protection, you are invited to look further at the relevant clauses of the Code.

Of course, installers and specifiers may install a system with greater safety features than laid down in the letter of the Code. For example, rather than a Grade E system landlords might consider it prudent to install a Grade D system instead. This is especially true considering the many restrictions that apply to the use of Grade E systems.

Battery Powered Smoke Alarms - Grade F

BS 5839: Pt.6 acknowledges the advantages of the single, battery powered smoke alarm. They are simple to install and offer protection at very low cost. Battery powered smoke alarms conforming to BS EN 14604:2005 are recommended. Battery powered smoke alarms are typically suitable for owner-occupied buildings (existing buildings) with up to two storeys. Please note: if your property has multiple levels, it is recommended to have interlinked alarms. This is to ensure you receive the earliest possible warning of fire.

Single story tenanted properties were allowed in the last version (2004) of this standard to be fitted with Grade F alarms. This has now been changed to a grade D requirement. As an aside, landlords have now been found liable in cases where tenants themselves have disabled an alarm. For this reason, it is unlikely that landlords will be able to trust tenants to adequately look after a smoke alarm. The Code highlights the fact that battery powered smoke alarms are also only suitable for owner-occupied properties if the likelihood is, that batteries will be replaced within five days of a low battery signal.

Mains Powered Smoke Alarms without Back-up Battery - Grade E

The Code does not recommend an application for alarms without back-up power source any longer. Grade E systems have serious drawbacks: power cuts or the termination of supply for whatever reason disables them totally. They can also be rendered useless by the tripping of a protective device, or even - in some cases - by the fire itself. Householders may also disable them at the mains all too easily if false alarms are a problem. Some organization only offering mains powered smoke alarms WITH back-up battery.

Mains Powered Smoke Alarms with Back-up Battery - Grade D

The problems outlined above can be overcome by using mains powered alarms that incorporate, within each alarm, a stand-by supply such as a primary or rechargeable battery. The alarms have to be interconnected either through wiring or radio-interlink. The mains power supply can come from a dedicated power supply directly from the fuse box or from the nearest permanently powered light fitting, as long as the smoke alarm heads can be removed without removing the base as well.

Grade D is required for new, owner-occupied buildings of up to three storeys, two storey rented properties and existing, owner-occupied buildings of more than two storeys. Very large storeys (>200m2) might require Grade B alarm system.

A question remains for landlords - can they be sure that their tenants are paying their electricity bills? Given that many tenants may have low incomes (in many local authorities, 70% or more of all tenants are on subsidised incomes), they may well experience periods of disconnection - and yet the landlord could well be liable if the alarm fails to sound because the tenant has not paid his or her bills! Unfair or not, as the law stands, it obviously makes good commercial sense to ensure that a reliable, ideally re-chargeable and sealed-in backup battery is in place.

The minimum back-up duration recommended is 72 hours, and the Code acknowledges that there could well be circumstances where a longer stand-by period is justified e.g. tenants' inability to pay their electricity bill.

Fire Detectors supplied with Power from a common

Power Supply Unit - Grade A, B, C

More expensive high specification systems can offer connection of all fire detection devices to a common power supply via low voltage transformers, or interlinked fire and security systems. Again, a minimum 72 hour back-up is recommended by the Code.

Levels of Protection - Categories of System

This relates to the level of protection afforded by the system.

Within the A - F grades defined earlier, the standard identifies three different categories of protection:

·       LD1 - A system installed throughout the dwelling, incorporating detectors in all circulation spaces that form part of the escape routes from the dwelling, and in all rooms and areas in which fire might start, other than toilets, bathrooms and shower rooms

·       LD2 - A system incorporating detectors in all circulation spaces that form part of the escape routes from the premises, and in all rooms or areas that present a high risk of fire to occupants

·       LD3 - A system incorporating detectors in all circulation spaces that form part of the escape routes from the premises

It is noted that an LD3 type system is intended to protect escape routes for those not directly involved in the fire and may not save the life of anyone in the immediate vicinity of the fire.

Only by quoting Grade and Category can a meaningful and effective alarm system be specified, e.g. Grade D, Category LD2.

Grade C

Grade C, LD1 Houses providing NHS supported living in the community. Dwellings (আবাস) of one, two or three storeys occupied by no more than six residents.

• Control and indication panel with battery back-up for use in sheltered housing

• Intruder alarm system may also support 12 Volt smoke and heat alarms

• Social alarm system may also support 12 Volt smoke and heat alarms

• Carbon monoxide detectors can be added to the system.

• System is designed in accordance with the recommendations of BS 5839-1 Sections 1-4 with BS 5839-6 clauses 13,14,18,15.20 and 21 replacing the similar clauses of BS 5839-1

• Fire detectors in all the communal areas (the fire-risk assessment may define that a heat detector and sounder should be located inside each flat, within 1 metre of the main door and directly connected to the communal system)

• Manual call points may be sited on the fire exit route of the common parts, at all storey exits and to the open air

• May be interconnected using radio links

• May be wired in standard non-fire resistant cable

• Requires a dedicated mains supply

• The sound pressure level of the alarm signal measured at the doorway of each bedroom with the door open should be at least 85dB(A), unless a fire risk assessment determines that the sound pressure level should be higher 75dB(A) at the bed head

• Where the design of the flat has no door separating the kitchen from the circulation or living space, a smoke detector may be used, subject to a fire risk assessment establishing that the kitchen extract system will be able to prevent false alarms being caused by food preparation

• Intruder and social alarm systems may be considered for connecting to an alarm receiving centre (ARC)

Grade C, LD2 Sheltered housing (individual dwelling units only) - New or materially altered dwellings or existing dwellings where the structural fire precautions are of a lower standard.

• Control and indication panel with battery back-up for use in sheltered housing.

• Intruder alarm system may also support 12Volt smoke and heat alarms

• Social alarm system may also support 12Volt smoke and heat alarms

• Carbon monoxide detectors can be added to the system

• Optical alarms in hallways and landings, heat detectors in the kitchen and lounge

• May be interconnected using radio links

• May be wired in standard non-fire-resistant cable

• Requires a dedicated mains supply

• The sound pressure level of the alarm signal measured at the doorway of each bedroom with the door open should be at least 85dB(A), unless a fire risk assessment determines that the sound pressure level should be higher. 75dB(A) at the bed head

• Where the design of the flat has no door separating the kitchen from the circulation or living space a smoke detector may be used, subject to a fire risk assessment establishing that the kitchen extract system will be able to prevent false alarms being caused by food preparation

• Intruder and social alarm systems may be considered for connecting to an alarm receiving centre (ARC)

Grade C, LD3 Sheltered housing (Individual dwelling units only) - Existing dwellings only.

• Control and indication panel with battery back-up for use in sheltered housing

• Intruder alarm system may also support 12Volt smoke and heat alarms

• Social alarm system may also support 12Volt smoke and heat alarms

• Carbon monoxide detectors can be added to the system

• Optical alarms in hallways and landings

• May be interconnected using radio links

• May be wired in standard non-fire-resistant cable

• Requires a dedicated mains supply

• The independent system in each unit should derive its mains supply from a dedicated supply

• The sound pressure level of the alarm signal measured at the doorway of each bedroom with the door open should be at least 85dB(A), unless a fire risk assessment determines that the sound pressure level should be higher. 75dB(A) at the bed head

• Where the design of the flat has no door separating the kitchen from the circulation or living space a smoke detector may be used, subject to a fire risk assessment establishing that the kitchen extract system will be able to prevent false alarms being caused by food preparation

• Intruder and social alarm systems may be considered for connecting to an alarm receiving centre (ARC)

Grade C, PD2 Property protection only where specified. These consist of - Single or two-storey dwellings. Other dwellings as PD1.

• Control and indication panel with battery back-up for use in sheltered housing.

• System is used solely for the protection of the property

• Fire detectors in a PD2 system would be installed in specified areas of the building.

• May be interconnected using radio links

• May be wired in standard cable

• System should have its own dedicated mains supply

• The system will generally have a minimum of two sounders, one of which will be on the external face of the building adjacent to the control and indication panel

• Will be connected to an alarm receiving centre (ARC)

Grade B

Grade B, LD2 New or materially altered dwellings or existing dwellings where structural fire precautions are of a lower level. Single-family dwellings and shared houses with no floor greater than 200sq metres in area. These consist of four or more storey houses. New or materially altered dwellings or existing dwellings where structural fire precautions are of a lower level. Single-family dwellings and shared houses with one or more floor greater than 200sq metres in area. These consist of maisonettes or two-storey houses.

• With the exception of the indicator panel the system should conform to BS 5839-1, and may accommodate fire detectors other than smoke and heat alarms

• Basic indication panel with battery back-up (conforming with EN 54-2, EN54-4 or annex C of BS 5839-6); this is not a standard panel; Consider using standard conventional fire alarm panel as used for Grade A system. This may be more competitive

• Optical alarms in hallways and landings, heat detectors in the kitchen and lounge. (Additional detectors may be needed subject to the fire risk assessment)

• May be interconnected using radio links

• Should be wired in standard fire-resistant cable, particularly for the mains supply

• System should have its own dedicated mains supply

• The sound pressure level of the alarm signal measured at the doorway of each bedroom with the door open should be at least 85dB(A), unless a fire risk assessment determines that the sound pressure level should be higher. 75dB(A) at the bed head

• Where the design of the flat has no door separating the kitchen from the circulation or living space a smoke detector may be used, subject to a fire risk assessment establishing that the kitchen extract system will be able to prevent false alarms being caused by food preparation

Grade A

Grade A, LD1 HMOs, Single-family dwellings and shared houses with one or more floors greater than 200sq metres. (Note: FSO guidance for sleeping risks allows HMOs of more than two storeys (more than one storey above ground), flats and conversions (including holiday flats) that have not been constructed to building regulation standards may have an LD2 category of system installed.)

These dwellings consist of - Three or more storey houses.

Houses of Multiple Occupation - Communal areas only.

• Conventional or addressable control and indication panel with battery back-up (conforming with EN 54-2 and EN 54-4) covering the communal areas

• Where rented individual flats are included these systems should be self-contained and installed to Grade D LD2 standard

• System is designed in accordance with the recommendations of BS 5839-1 sections 1-4, with BS 5839-6 clauses 13,14,18,15.20 and 21 replacing the similar clauses of BS 5839-1

• Fire detectors in all the communal areas (the fire risk assessment may define that a heat detector and sounder should be located inside each flat, within 1 metre of the main door and directly connected to the communal system)

• Manual call points should be sited on the fire exit route of the common parts at all storey exits and to the open air

• May be interconnected using radio links

• The communal system should be wired in standard or enhanced fire-resistant cable; this includes the mains supply

• The communal system should have its own dedicated mains supply

• The independent system in each flat may derive its mains supply from a dedicated supply or a regularly used local lighting circuit

• Each system in the flats may be wired in non-fire-resistant cable

• If a conventional control and indicating panel is used, a remote indicator should be located outside the flat or the flat number or the location should be indicated in text on an addressable control and indication panel

• The sound pressure level of the alarm signal measured at the doorway of each bedroom with the door open should be at least 85dB(A), unless a fire risk assessment determines that the sound pressure level should be higher. 75dB(A) at the bed head

• Where the design of the flat has no door separating the kitchen from the circulation or living space a smoke detector may be used, subject to a fire risk assessment establishing that the kitchen extract system will be able to prevent false alarms being caused by food preparation

• Depending on the fire risk assessment the communal system may be connected to an alarm receiving centre (ARC)

Grade A, PD1 as LD1 above. PD2 Property protection of dwellings only where specified (no sleeping risk), see recommendations below. This is usually for insurance purposes.

• Conventional or addressable control and indication panel with battery back-up (conforming with EN 54-2 and EN54-4)

• System generally specified by insurers and is solely for the protection of the property

• System is designed in accordance with the recommendations of BS 5839-1 sections 1-4 with BS 5839-6 clauses 13,14,18,15.20 and 21 replacing those of BS 5839-1

• Fire detectors in a PD2 system would be installed in defined areas of the building. On the rare occasion that a PD1 system is specified the detectors would be located throughout the building except toilets, bath and shower rooms

• May be interconnected using radio links

• Should be wired in standard or enhanced fire-resistant cable; this includes the mains supply

• System should have its own dedicated mains supply

• The system will generally have a minimum of two sounders, one of which will be on the external face of the building adjacent to the control and indication panel

• Will be connected to an alarm receiving centre (ARC)

You can buy the full BS 5839-6:2013 standard online.

History of BS 5839-part 6

When first introduced in 1995, the BS 5839: Pt.6 Code of Practice became the most important set of recommendations ever made on fire safety in the home.

It had an immediate impact on architects, system designers, installers and landlords in the private or public sector, all of whom were required to familiarise themselves with these important recommendations. Landlords in particular needed to abide by these recommendations, as legal liability with regard to 'duty of care' would undoubtedly become a serious issue should a fire occur in an inadequately protected property.

In short, BS 5839: Pt.6 became the essential guide to providing adequate fire protection in all dwelling types.

In September 2004, the Code of Practice was extensively revised and updated by the publication of BS 5839: Pt.6: 2004 which superseded BS 5839: Pt.6: 1995, which is now withdrawn. The changes therein are important and need to be fully understood and appreciated by all those with responsibility for fire safety in domestic dwellings.

An updated standard came out in 2013 and included for the first time common areas in sheltered housing. Carbon monoxide detectors were also permitted as fire alarm sensors and the requirement for rented accommodations were tightened.

Types of Detector

Optical Alarms - where should they be used?

Optical sensors are more responsive to smouldering fires producing large particle smoke typical of fires involving furniture and bedding. They are more immune to invisible smoke produced by ‘burning the toast’ and similar cooking fumes. This makes them ideal for locating in hallways close to kitchens, where false alarms from ionisation alarms may be a particular problem. BS 5839: Pt.6: 2013 recommends the use of optical alarms in circulation spaces of a dwelling, such as hallways and landings. Optical alarms are prone to false alarm if exposed to steam and should not be located too close to poorly ventilated bathrooms or shower rooms.

1. A light beam is pulsed in the sensor chamber every 10 seconds to ‘look’ for smoke. Any smoke present has to be visible to the naked eye so that the receptor can ‘see’ it. If no smoke is detected, the alarm will remain in a standby state.

2. When large particle smoke is detected, the light beam will be scattered onto the light receptor.

3. This will then send an electrical signal to the Integrated Circuit (IC).

4. If the IC receives two consecutive signals, the alarm will sound.

Heat Alarms - where should they be used?

Heat alarms are less likely to cause false alarm problems, as they are not responsive to any type of smoke or fumes. They only detect heat. This type of detector will provide a slower response than smoke alarms. All of the alarm units should be inter connected. BS 5839-6: 2013 recommends that heat alarms should be used in kitchens. It goes on to suggest that they may also have a role to play in the main living room but they should not be installed in circulation spaces or areas where fast response to fire is required.

1. A thermistor (a heat sensitive resistor) is sited in the sensor chamber of the alarm.

2. When heat is detected the thermistor will send an electrical signal to the Integrated Circuit (IC).

3. If the IC receives two consecutive signals the alarm will sound.

Ionisation Alarms - where should they be used?

Ionisation sensors are particularly sensitive to the almost invisible smoke produced by fast flaming fires. This makes them more liable to false alarm due to cooking fumes if sited in a hallway close to a kitchen. Ionisation alarms are less vulnerable to false alarms caused by dense tobacco smoke, excessive dust or insect ingress. BS 5839: Pt.6: 2004 recommends that ionisation alarms should not be used in hallways and landings, where there is a risk of false alarms caused by cooking fumes.

1. An Ionisation detector is designed to provide an early warning of a fast burning fire (not smoke). The ionisation device has two electrodes within an ionisation chamber, between which a measured resistance of negative ions flow. This circuit is connected to a potential divider in the Integrated Circuit (IC), which remains in a constant closed standby state.

2. In consuming fuel, fire creates combustion gas, which gives off positive ions. When these positive ions enter the ionisation chamber, the positive ions join themselves to the negative ions flowing from the radioactive source and between the electrodes, changing the resistance of the flow.

3. The resistance is applied to the potential divider in the IC and allows current to flow.

4. If the IC receives a continuous signal, the alarm will sound.

Location and Positioning of Fire Detectors

When siting detectors in a hallway, no smoke detector should be more than 7.5 metres horizontally from any point in the hallway. In rooms, again no smoke detector should be sited more than 7.5 metres from any point of the room. For heat detection, this distance should be reduced to 5.3 metres. No smoke alarms should be installed less than 300mm from any wall or beam. In a room or hallway, 10m x 10m or 50 m2 where ceiling mounting is impractical, detectors may be mounted on the wall between 150mm and 300mm from the ceiling.

Do not install smoke or heat alarms in bathrooms, shower rooms or toilets, except where the fire risk assessment identifies a specific need e.g. the presence of a boiler.

Note: For roofs with a pitch deeper than 600mm, smoke detectors should be within the top 600mm and heat detectors within 150mm. Allow increased coverage over 7.5m for smoke detectors and 5.3m for heat detector spacing’s due to the angle of the roof which will then be applicable at 1% for each degree of slope up to a maximum of 25%.

Typical three floor house (HMO) with flats and apartment units on each floor, installed to Grade A (BS 5839-1) Category LD3 in the units and L3 in the common areas.

The diagram below shows a house converted into flats (HMO). In this typical system each flat has its own dedicated system (see the symbol above). There is also a communal system, which covers the escape routes and rooms opening onto the escape routes.

Should a false alarm occur in any of the flats, it will not affect any of the others. Some specifiers require that if a flat is unoccupied and a fire occurs, a heat alarm inside the flat (connected to the escape route system, but not the system in the apartments) will operate the communal system in the escape routes plus the heat alarm adjacent to the main entrance door in each of the other flats, thus providing a vital early warning.

Use of manual call points

Manual call points should be provided in very large single-family dwellings or student accommodation. This will also generally apply to houses with four storeys or more, multi-storey mansions, country houses and houses of multiple occupation (HMO).

It would be appropriate to consider the use of manual call points in all Grade A systems.

Alarm Systems for the Deaf and Hearing Impaired

BS 5839-6 makes recommendations for people with hearing difficulties who require a different approach to fire protection, as a conventional alarm sounder will probably not be sufficient for their needs.

Those with hearing difficulties will need to use strobe units and a vibrating pad located under the pillow. This equipment can be connected to the Grade A, B, C or D systems either by hard wire or wireless (radio) installation.

Audibility of Fire Alarm Warning Devices

A fire detection and alarm system only provides satisfactory protection if it is capable of rousing at least the principal occupants of the dwelling. It is known that greater sound levels are required to rouse children, older people with poor hearing and impaired persons (alcohol and drugs). International tests have shown that from these groups 120dB(A) has failed to wake some of those tested.

As we have identified earlier, BS 5839-6 recommends 85dB(A) at the doorway of each bedroom (with the door open). A closed door can reduce this by as much as 30dB(A). The document does, however, go on to say that higher levels may by required to rouse certain groups of people. The international research regarding sound pressure levels suggests that 75dB(A) at the bed head is a minimum sound pressure level and that even this may not be enough. Whilst the text of BS 5839-6 identifies this sound pressure level it makes no specific further recommendation, stating only that higher sound pressure levels should be determined as part of a fire risk assessment.

Great care should be taken when installing systems in buildings such as single-family dwellings, where there is likely to be no fire risk assessment available. Such an assessment should be carried out in close consultation with the occupants, building control or the person responsible for the dwelling. It is not the installer’s responsibility to specify sound pressure levels outside those recommended by BS 5839-6. However, you should be able to draw the attention of the interested persons to the existence of this particular risk.

Zoning of Systems

Zoning is generally restricted to Grades A, B, and C systems. These are systems which will have a control and indicating panel. In most dwellings the zonal configuration would be on a floor-by-floor basis. However, in larger HMOs there will probably be a complex zone configuration and even a cause and effect matrix. In these buildings addressable systems would be appropriate.

• For Grade A systems in HMOs there should be a means of identifying the dwelling unit where the fire signal originated. This could be addressable text or a remote indicator outside each flat. The panel should be compliant with EN 54.

• For Grade B systems each floor is generally treated as a zone. This does not need to be an EN 54 panel, although it may be cheaper to use a standard small EN 54 panel than to build one with the lesser facilities allowable in this Grade of system.

• Grade C systems do not normally need to be divided into zones for fire.

Wiring & Installation

The wiring of fire alarm and detection systems is carried out in accordance with BS5839 Parts 1 and 6, which reference compliance with BS 7671 Requirements for Electrical Installations (IEE Wiring Regulations Seventeenth Edition).

• Grade A systems recommend the use of fire-resistant cables

• Grade B systems recommend the use of fire-resistant cables

• Grade C systems recommend that cable should be suitable for the current and voltage of the circuits concerned

• Grades D and E cables used may comprise of any cable suitable for domestic wiring

• Grade F cables used to interconnect the battery powered smoke alarms may be any type of cable suitable for the current and voltage concerned

Maintenance & Servicing

System maintenance is critical in the performance of the system over its lifetime. The system users should be encouraged to have their systems maintained at the appropriate intervals by a competent person.

• To comply with BS 5839-6 recommendation, BS 5839-1 based Grade A systems should be inspected at periods not exceeding six months

• Grades B and C systems should be inspected at periods not exceeding six months

• Grades D, E and F systems should be tested and cleaned in accordance with the manufacturer’s instructions

• Weekly sound checks by the user

• System servicing should be carried out by an organisation that can provide 24-hour service availability and by competent service and maintenance personnel.

System Certification

Upon completion of a system, the appropriate certificates should be completed and signed by a competent person.

1) Grade A system (BS 5839-1/6)

a) BS 5839-6 Design certificate

b) BS 5839-6 Installation certificate (plus a BS 7671 Electrical Installation Certificate to support the registration for a Part P Certificate)

c) BS 5839-6 Commissioning certificate

d) BS 5839-6 Acceptance certificate

2) Grades B, C, D, E and F systems (BS 5839-6)

a) BS 5839-6 single certificate should be completed for all the above types of system (and should include a BS 7671 Electrical Installation Certificate or a Minor Electrical Installation Works Certificate to support the reporting procedure for a Part P Certificate)

Documentation

The installer is required to provide documented information to the interested parties relating to the maintenance and operation of the system which has been installed. This, in the case of small systems D, E and F, may be as little as the manufacturer’s instructions.

BS EN 54: fire detection & alarm systems

BS EN 54-1:2011 - Introduction

BS EN 54-2:1997+A1:2006 - Control and Indicating Equipment

BS EN 54-3:2001 - Fire alarm devices: sounders

BS EN 54-4:1998 - Power supply equipment

BS EN 54-5:2001 - Heat detectors: Point detectors

BS EN 54-7:2001 - Smoke detectors: point detectors using scattered light, transmitted light or ionization

BS EN 54-10:2002 - Flame detectors: point detectors

BS EN 54-11:2001 - Manual call points

BS EN 54-12:2002 - Smoke detectors: line detectors using an optical light beam

BS EN 54-13:2005 - Compatibility assessment of system components

BS EN 54-16:2008 - Voice alarm control and indicating equipment

BS EN 54-17:2005 - Short-circuit isolators

BS EN 54-18:2005 - Input/output devices

BS EN 54-20:2006 - Aspirating smoke detectors

BS EN 54-21:2006 - Alarm transmission and fault warning routing equipment

BS EN 54-22:2015 - Resettable line-type heat detectors 

BS EN 54-23:2010 - Fire alarm devices. Visual alarm devices

BS EN 54-24:2008 - Components of voice alarm systems: Loudspeakers

BS EN 54-25:2008 - Components using radio links

BS EN 54-26:2015 - Point fire detectors using carbon monoxide sensors 

BS EN 54-29:2015 - Multi-sensor fire detectors – Point detectors using a combination of smoke and heat sensors 

BS EN 54-30:2015 - Multi-sensor fire detectors – Point detectors using a combination of carbon monoxide and optionally heat detectors  

BS EN 54-31:2014 - Multi-sensor fire detectors – Point detectors using a combination of smoke, carbon monoxide and optionally heat sensors