4 February 2019
What to Consider in Hospital Fire System Design
Hospitals are seen as places of refuge, a relief centre for those who are weak and sickly, above all a safe place. Any building fire is horrific, but the thought of a fire in a hospital is a terror of a different kind, and so fire systems must be planned and designed with great care and attention to detail.
Fire system design is complex in general and tailored for each building, involving a holistic approach, analysing building components in their totality. For hospitals, beyond code compliance and legal responsibilities, fire design service providers must consider different parts of the fire systems design process and what individual systems are most suitable.
For any design, code compliance is an important first step. Building owners, management, architects, engineers, contractors and consultants all need to be involved in the planning and design process and be cognisant of the respective codes. A key fire protection goal is to extinguish fires as early as possible and clear up escape routes.
Fire-protection system goals include the need to save lives, save property and preserve business continuity. Hospital fire systems must include components for detection, alarms and notification and suppression. These components must work cohesively to detect, contain, control/extinguish early stages of the fire and survive advanced stages. Ideally, a fire-protection engineer should be on board early in the design process.
Typically, a specialist fire design engineer is appointed for commercial and healthcare projects, usually with the experience of similar projects and the ability to understand building use and the impact of other building services on fire design. Once appointed, the fire design engineering team will address each of the three stages of fire system design. Firstly, fire systems design involves detecting a fire. Secondly, it involves notifying people to the presence of a fire, and thirdly, it involves the procedure to extinguish the fire. Looking at them in order, we first consider detection:
Intelligent smoke detectors sense smoke, trigger alarm systems and can determine different alarm thresholds.
Heat detectors trigger alarms and notification systems, sometimes before smoke detectors.
Different fire components, such as flames, smoke, flue gas and heat, need appropriate sensors and detectors so that the signals can be transmitted instantaneously via data bus to a fire detection system. Fire detection control panels can be set up to monitor large hospitals while having a clear view of everything to do with fire protection.
Alarms & Notification Systems
Notification of fire includes alarms, and these have become increasingly complex, with increased functions, for example:
Alarm systems ideally will have two objectives: to alert building occupants and to alert emergency public responders (police and fire agencies) for an immediate response. Certain alarm systems can direct first responders to exactly where the fire is located.
Software, such as AutoCAD, can help develop floor plan integration to help do this. As an alarm rings, an AutoCAD screen can show the floor where the alarm went off and provide a computer print-out of it. The floor plan showing where the alarm was activated can be handed over to first responders by the security staff. Instead of spending precious time trying to locate the exact site of the fire, responders know exactly where to go.
Speakers are an additional feature of alarms, replacing or in addition to, bell-type alarms. Alarm systems can include functions such as closing fire doors, recalling lifts and monitor fire suppression systems, such as sprinklers. Critical systems, such as a building’s ventilation, smoke-management and stairwell-pressurisation systems can also be connected with the alarm systems.
The third part of fire systems design involves the actual attempt to extinguish the fire, or suppression.
A key part of fire systems design is the suppression system installed. The most popular and widely used system of suppression in hospitals is the sprinkler system. Having a working sprinkler system saves 50-67% of casualties and property loss during a fire, compared to a place without sprinklers, according to the National Fire Protection Association (NFPA). A heat-sensitive element resides within each independently operating sprinkler. This element reacts to the heat from a fire and heats up the sprinkler and activates the sprinkler head.
Places where sprinklers cannot be used due to the possible damage of equipment or inventory, fire systems designers must suggest alternative gaseous or chemical fire-suppression systems.
Of course, when there are no fires, the fire systems must be properly maintained.
An important factor affecting fire systems design is maintenance. A system that is not regularly maintained will not be reliable and thus will be ineffective.
Specifically for Hospitals
Smoke detectors can be placed throughout the hospital premises to detect fires initially so that the rescue and evacuation process can begin. Simultaneously, sprinkler or fine water spray systems are automatically activated to try and extinguish the fire before it spreads. Hazardous areas in hospitals may have fire extinguishers, hydrant systems and corresponding standpipes. It’s worth looking at some of the fire suppression systems or a combination that work well for hospital premises.
Fire Extinguishing Systems
During a fire, electrical and electronic switchgears that control many hospital devices may be damaged to such an extent that entire sections and functions of a hospital may be affected or completely destroyed. Walk-in and lockable switch and cable rooms must use argon and nitrogen extinguishing solutions for protection and minimise human risks. These are non-toxic, environmentally friendly gases that douse electrical fires without leaving residue.
Sprinklers are activated automatically in case of fire and actively help stop the fire from spreading. Pipes and sprinklers run through protected areas of the hospital. Only sprinklers in the vicinity of the fire are activated. A bulb filled with liquid seals the sprinkler. When the sprinkler becomes hot, the glass bulb breaks. The extinguishing water kept under pressure flows into the sprinkler, where the water is distributed to the affected area by a deflector and the water falls on the flames. Sprinklers can be connected to an alarm system also.
Water Mist Extinguishing Systems
Low-pressure water mist extinguishing systems use a relatively small amount of water but have an effective extinguishing effect. They can be used in low-level fire hazard areas, such as offices and patient rooms. Water mist systems reduce the amount of water required for extinguishing by up to 85% in special sprinklers. Targeting the mist can effectively extinguish the fire. For cable channels, almost 70% of the available water in the system is saved.
High-pressure water mist systems employ micro droplets through nozzles to affected areas. The system typically consists of a high-pressure modular pump unit, section valves, small pipes and water mist nozzles and results in wide coverage, with decreased water consumption. The design may include a compact skid unit for reliability and affordability. High-pressure water is forced through nozzles, forming a fine mist with a two-part effect – the fire is cooled rapidly, and the flames are starved of oxygen to reduce damage and extinguish fires.
High-pressure Water Mist Benefits
Rapidly and efficiently extinguishes the fire
- Consumes minimum amount of water
- Efficiently blocks radial heat, protecting against structural damage by not allowing the flames from spreading
- Small water droplets will be gentle on hospital electrical equipment, maintaining its functionality and keeping data safe
- Lower installation costs, less time and less service interventions result from fewer nozzles, optimized spacing and one pump for all applications
- Water-lubricated high-pressure pumps need less maintenance
- Water supply costs are significantly less, due to less piping, less water requirement and significantly smaller water reservoirs
- Sensitive areas, such as server rooms and archives, benefit from water mist systems, as they cause minimum damage
Why Water Mist Technology Is Ideal for Hospital Fire Protection
Safe patient and staff evacuation
- In a hospital, the safe evacuation of patients and staff is minimally affected by water mist.
- The water mist system is only activated in zones where fire is detected. Other hospital areas remain unaffected.
- Since the pipes are small, they are easy to bend and install.
- The system can be seamlessly integrated with electrical, mechanical and plumbing equipment in a hospital.
- With the water exiting corrosion-resistant stainless steel pipes being clean, overall clean-up is easier, faster and less costly, resulting in less damage.
Simple and Modular
- The high-pressure water mist system is easy to install in hospitals.
- As it is a compact modular system, it can be easily adapted to cover any new hospital sections.
Water Spray Systems
Hydraulic systems of waste facilities and transformers are places where fires could start easily due to fuels and lubricants being subjected to high temperatures. Water spray systems can be triggered hydraulically, pneumatically or electrically so that the open nozzles spray water quickly and effectively.
External hydrants and wall hydrants are connections to reliable supplies of extinguishing water. They help fire brigades, operating staff and building users.
Foam Extinguishing Systems & Foam Monitors
Bigger, more well-established hospitals have helicopter pads. Helicopters are potential hazards due to the kerosene, hydraulic oil and hot turbines they have. Foam cannons, or monitors, have the ability to cover burning liquids, making them airtight and cooling them down.
Systems for Kitchens
Hospital kitchens have the potential for many hazards and a fire added to the mix could make for a disastrous situation. Specially designed for kitchens, compact extinguishing systems can be triggered in seconds to protect the space around a fire, while food preparation can continue nearby.
The various components of fire systems design within the context of other building services requires a combined approach from different design engineers, and therefore experienced and technically qualified HVAC mechanical engineering consultants, electrical design services engineers and hydraulics and plumbing design services engineers are required along with the skilled fire design engineering specialists. The need to deliver fire design as part of a wider building services design solution at lower cost and within deadlines has resulted in many firms using offshore design support teams. Such teams now possess sound knowledge of fire design codes and regulations and as such outsourcing firms have become effective fire design services providers to many Western-based firms in the UK, USA, Canada and Australia.