Lerch Bates Inc. Building Insight

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Building Life Safety — The Basics

One of the primary concerns of building owners and managers is the safety of the occupants in their buildings. Life Safety is an integral part of almost all buildings, but some building owners and managers may not fully understand these systems, the reasoning behind them, the way they work, and the ways in which they need to be maintained.

Life Safety begins with the methods of construction used in each building and proceeds through the installation of specialized systems to protect the occupants from fire and other calamities.

Each building in the United States is built to meet a complex web of standards and regulations known collectively as “the code”. There are building codes, fire codes, plumbing codes, electrical codes, mechanical (or HVAC) codes, elevator codes, and more. Codes in almost all jurisdictions are based on “model codes” which are generic codes produced by private organizations dedicated to the task. Cities, counties, and states then take that material, add or subtract any items that may be of local concern, and adopt the finished product as their legal code. Most legally adopted codes however, are still very close to the model codes, so we can make a lot of generalizations about the legal code requirements in almost all jurisdictions.

The first fire safety aspect of any building is its basic design and floor layout. For instance, every building must have a certain number of emergency exits and each exit must be a certain maximum distance from each occupant, depending on the type and number of occupants and the size of the building.

Next, buildings must be constructed using fire resistive materials and fire resistive design. Stairwells, corridors, and elevator lobbies are all required by code to be isolated from the rest of a building by fire walls or doors designed to resist penetration from fire for a certain time of ten one hour or two hours. Open spaces can be divided by fire rated walls, cutting down on the potential for the spread of a fire.

The next layer in building fire safety is the design and installation of specialized systems to detect or extinguish a fire, and to facilitate the safe evacuation of the occupants of the building.

Fire alarm systems are required in many types of residential and commercial buildings as well as all hospitals, schools, day care centers, nursing homes, places of assembly, and high rises. Fire alarm systems detect the presence of a fire with automatic smoke and heat detectors and also provide manual pull stations, generally at each exit, that enable the building occupants to manually alert others in the building and the appropriate authorities of a fire condition. A fire alarm, when activated either by automatic or manual means, will usually sound a loud alarm throughout the facility where it is located and send some type of emergency signal to a guard station in the building or to an off site central monitoring station. That monitoring station will in turn notify the fire department.

Fire alarm systems work in conjunction with fire sprinkler systems. Sprinkler systems are required in even more types of buildings than are fire alarm systems. Fire sprinkler systems consist of a large network of water pipes running throughout a building ending in sprinkler heads, which usually appear on the ceiling. These sprinkler heads are equipped with a type of thermal link which opens or breaks after sensing an ambient temperature above its rated temperature level, causing that sprinkler (not all of the sprinklers, as depicted in the movies,) to open and release a spray of water. When any sprinkler opens, the resulting flow of water in the pipes triggers a special water flow sensor, activating the building fire alarm and usually alerting the occupants and the authorities. Some sprinkler systems are installed in buildings with no fire alarm system and those systems usually are required to notify the fire authorities of a fire condition, although they may not sound an alarm for the building occupants.

Other non emergency building systems work with the fire alarm system to ensure occupant safety. In most cases, following an alarm sent to the fire alarm system, some or all of the air conditioning and heating fans will be automatically turned off to slow the spread of fire. Some doors located within fire rated walls may be automatically closed, also to prevent the spread of fire. And any elevators will usually be automatically returned to the ground level and deactivated so that the occupants do not risk accidentally traveling to a dangerous floor or being trapped in a disabled elevator.

A system provided in virtually all buildings to ensure safety during an evacuation is the emergency lighting and exit sign system. Emergency lights consists of battery or backup generator powered lights that will automatically turn on when regular electrical power fails, whether from within the building or because of an outside electrical utility problem. These lights are usually arranged to provide at least a usable path of light to the building exit. Exit signs are directional indicators provided to point the way to the exit. Exit signs are also always backed up by emergency power.

These are the major components of building life safety. Each one of these paragraphs scratches the surface of a complex subject. In subsequent entries I will try to provide more information on each of these topics.

I would like your input on further items of interest to building owners and managers within the topic of fire alarm and life safety. Please feel free to comment with ideas.

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