Diverse detection for a diverse environment
A good start for a hotelier is to understand the site’s fire and life safety requirements and determine which products can fulfill them. A diverse environment needs a cohesive plan that delivers data from individual monitoring systems to a single point where a qualified operator can respond instantly. To get there, a hotel manager needs to look at the total property as a suite of different spaces and install a suite of different products to protect it. Essentially, the plan, the personnel, the training, the devices, the panel, the network, and the first responders create a unique communication system customized to a particular property’s fire and life safety needs.
Correct Installation of Hotel/Motel Smoke Detectors
The fire protection codes for hotels require a detection/notification system in each room. A system of interconnected smoke detectors should be installed, with units in every room, including common areas and all non-guest rooms. If they are installed in compliance with nationally recognized standards, the alarm system will alert guests who are at risk. It is also important that the alarm system be monitored offsite by a qualified organization, for example, a central station alarm company that has an Underwriters Laboratories (UL) certificate. Some alarm systems are connected directly to the fire department, which is even better.
In addition, some jurisdictions are including system-connected carbon monoxide detectors in new ordinances. In fact, UL requires manufacturers of system-connected carbon monoxide detectors to apply the same critical life safety supervision concepts used for smoke detection devices, in order to prevent undetected device failures.
In large hotels, the building codes now require a fire department control station. This is a protected area where the fire alarm panel is located. The fire officer in charge will use it to monitor all of the building controls and manually operate some equipment, such as smoke control devices. The control station also has a communication system so the officer can send voice instructions throughout the hotel. Hotels may not have this item as part of the alarm system if they were built prior to the requirements being placed in the building code.
Where to install?
The goal of a fire detection system is to provide an accurate, early warning of a developing fire in any area of a building. Even pockets of unoccupied space require protection, because detectors may not quickly sense a developing fire on the far side of a wall or behind a closed door, allowing damage to spread needlessly.
The correct placement of detectors is also important for reliable operation. In general, when only one detector is required in a room or space, it is best to install a ceiling-mounted detector as close to the center of the room as possible. If a central ceiling location is not viable, for example, due to wiring constraints, the detector must have sufficient “open space,” with its edge no closer than 4 inches from a wall. Likewise, a wall mounted detector must clear between 4 and 12 inches from the top of the detector to the ceiling (see Fig. 1).
Another consideration for a total coverage plan is the proximity of detectors to the air handling system. NFPA 72 discusses the potential for detector malfunction if installation is in the path of an airflow supply or return duct. A smoke test to monitor particulate direction and velocity is helpful in determining detector placement. Smoke tests reveal potential causes of unwanted alarms, such as an airstream directed at the detector, which could result in dust accumulation that alters sensitivity levels.
How to space?
Placing detectors 30 feet apart to protect 900 square feet is the NFPA 72 standard for areas with smooth ceilings and no physical obstructions between ceiling and room contents. An example of an obstruction could be floor-toceiling shelves stacked with materials. Variables for ceiling height may also be calculated into spacing requirements based on the amount and nature of combustibles present.
One can determine the appropriate detector coverage for the standard 30 feet spacing by mapping the shape and dimensions of an area and then drawing a circle with a radius of 21 feet. A single detector may protect any square or rectangle that fits within the circumference of that circle (see Fig. 2). The technique shows that in a hallway measuring 10 feet wide, two detectors can protect up to 82 feet of the length (see Fig. 3).
Tags: Smoke detection
Posted in Audible/Visible Notification, Cover Features, Hospitality, Spring 2008
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