Module 4_Life Safety Concerns.pdf

LIFE SAFETY Module No. 4 CE 2211 – Building Systems Design UST Civil Engineering Department Engr. Katrina Camille D. Mendoza Hazard...

LIFE SAFETY Module No. 4 CE 2211 – Building Systems Design UST Civil Engineering Department Engr. Katrina Camille D. Mendoza Hazard Risk A hazard poses the threat Risk is the probability that the that an unwanted event, event will occur. possibly a catastrophe, may occur. Design Life of Buildings Design of buildings for both normal and emergency conditions should always incorporate a safety factor against failure. The magnitude of the safety factor should be selected in accordance with: the importance of a building the extent of personal injury or property loss that may result if a failure occurs; and the degree of uncertainty as to the magnitude or nature of loads and the properties and behavior of building components. Protection against Wind Wind Protection Pressures are considered positive when they tend to push a building component toward the building interior. They are treated as negative for suctions or uplifts, which tend to pull components outward. Wind Failure Modes Consideration of the ways in which winds may damage or destroy buildings suggests provisions that should be made to prevent failures. Past experience with building damage by winds indicates buildings are likely to fail by overturning; sliding; separation of components; excessive sway, or drift; or structural collapse. Light- weight and open-sided structures may be subject to failure either partially, or wholly, due to uplift. Protection against Earthquake Protection against Earthquakes Buildings should be designed to withstand minor earthquakes without damage, because they may occur almost everywhere. For major earthquakes, it may not be economical to prevent all damages but collapse should be precluded. Soil Liquefaction Occurs when a saturated or a partially saturated soil substantially loses strength and stiffness Landslides A landslide is the movement of rock, earth or debris down a sloped section of a land. Earthquake Characteristics Accelerations are recorded in accelerograms, which are a plot of the variation with time of components of Earthquakes are produced by sudden the ground accelerations. release of tremendous amounts of energy within the earth by a sudden movement at a point called the hypocenter. The point on the surface of the earth directly above the hypocenter is called the epicenter.) Seismic Scales For study of the behavior of buildings in past earthquakes and application of the information collected to contemporary aseismic design, it is useful to have some quantitative means for comparing earthquake severity. Two scales, the Modified Mercalli and the Richter, are commonly used. Protection against Water  PROTECTIVE MEASURES Whether thrust against and into a building by a flood, driven into the interior by a Floodproofing heavy rain, leaking from plumbing, storm surge, or seeping through the exterior Waterproofing enclosure, water can cause costly damage to a building. Consequently, designers should protect buildings and their contents against water damage. Roof Drainage Protection against Fire There are two distinct aspects of fire protection: life safety and property protection. Absolute safety from fire is not attainable. It is not possible to eliminate all combustible materials or all potential ignition sources. The standards most widely adopted fire protection design paramaters are those published by the National Fire Protection Association (NFPA) Underwriters Laboratories, Inc. (UL) publishes testing laboratory approvals of devices and systems in its ‘‘Fire Protection Equipment List,’’ updated annually and by bimonthly supplements. Classes of Fires  Fire Suppression Systems Fire Suppression Systems Automatic Sprinkles Standpipes Smoke and Heat Venting Ventilation facilities should be provided in addition to the protection afforded by automatic sprinklers and hose stations. Emergency Egress The arrangement of exit facilities should permit occupants to move freely toward exits that they can see clearly and that can be reached by safe, unobstructed, uncongested paths. The paths should be accessible to and usable by handicapped persons, including those in wheelchairs, if they may be occupants.  Egress Components Many building codes define an exit as a safe means of egress from the interior of a building to an open exterior space beyond the reach of a building fire or give an equivalent definition. A means of egress is a continuous, unobstructed path for evacuees from any point in a building to a public way. Types of Exits Building codes generally recognize the following as acceptable exits when they meet the codes’ safety requirements: Exit passageways Exit Doors Horizontal Exits Types of Exits Interior stairs Smokeproof tower/ Exterior stairs stair vestibule Types of Exits Escalators Moving Walks Construction Safety Construction Safety Safety Management is required by DOLE RA 11058 – Occupational Safety and Health Standards Law Samples of Unsafe Acts Unauthorized Failure to Removing/destroyin Using defective operation of warn/secure g safety devices equipment/tools equipment Improper Using PPE placement/lifting/ Operating at Horseplay improperly improper speed loading Samples of Unsafe Conditions Defective Congestion or Inadequate Inadequate tools/equipment/ restricted body guards/barriers warning systems materials movement Poor Extremes of Fire/explosion housekeeping/ Noise/radiation temperature/ hazards exposure disorder ventilation Construction Hazards Open Excavation Falling Objects Welding Operations Dust Dirt Temporary Wirings Temporary Overhead Electrical Lines Lightning Protection Lightning, a high-voltage, high- current electrical discharge between clouds and the ground, may strike and destroy life and property anywhere thunderstorms have occurred in the past. Buildings and their occupants can be protected against this hazard by installation of a special electrical system. Objectives of lightning protection are life safety, prevention of property damage, and maintenance of essential services, such as electrical and communication systems. The key element in diverting lightning away from a building is an air terminal or lightning rod, a conductor that projects into the air at least 12 in above the roof. Protection Against Intruders Prevention of illegal entry into buildings by professional criminals determined to break in is not practical. Hence, the prime objective of security measures is to make illegal entry difficult.  Security Center The security center may be equipped with or connected to electronic devices that do the following: Detect a break-in attempt and sound an alarm Identify the point of intrusion Turn on lights Display the intruder on closed-circuit television and record observations on videotape.  Notify the police. Limit entry to specific spaces only to approved personnel and only at permitted times. Change locks automatically.  END OF MODULE UST Civil Engineering Department Engr. Katrina Camille D. Mendoza