Plant Fire Safety - Chapter 4 PDF

Plant Fire Safety • Chapter 4 == OBJECTIVE ( 3 Explain fire prevention. The safest fire is one which is never given a chance to start! The best method of dealing with a fire is to prevent the fire from occurring in the first place. Various methods of fire prevention will be described in this ob...

Plant Fire Safety • Chapter 4 == OBJECTIVE ( 3 Explain fire prevention. The safest fire is one which is never given a chance to start! The best method of dealing with a fire is to prevent the fire from occurring in the first place. Various methods of fire prevention will be described in this objective. Some examples of ways to prevent fires are: a) Keep areas free and clear of debris. b) Remove flammable material from the location. c) Store flammables in the proper areas and building structures, or in equipment built from non-flammable or fire resistant material. FIRE RISK ASSESSME NT An effective method of fire prevention is to assess the possibility of a fire occurring in any location of a working environment. Reviewing an area for risks can result in the implementation of simple procedures. For example, storing flammable materials in self-contained areas that are located a safe distance away from any ignition source. A fire risk assessment can identify potential fire hazards and reduces the threat of a fire occurring. c The Canadian Centre for Occupational Health and Safety provides rules for risk assessments, which can be applied to Fire Risk Assessment: a) Identify fire hazards b) Evaluate the risk associated with that fire hazard c) Determine appropriate ways to eliminate or control the fire hazard Competent or qualified individuals, such as Power Engineers, should assess all areas of the plant for fire hazards. These individuals should be familiar with both fire and safety practices, and with the plant itself. The intent is to: a) Identify any hazards. b) Evaluate the possibility of a fire starting and the severity of the impact. c) Develop steps to take to ensure the fire does not happen. Identifying fire hazards may involve the inspection of the workplace by a designated party, for example, the fire and safety committee or representative. The inspector may use tools such as: a) Checklists. b) Documents identifying the types of material in the area for their flammability potential. c) On the job experience to determine where and how a fire hazard may exist. It is not unusual to discover flammable material that has "always been stored there" and was previously overlooked in the past. 4th Class Edition 3 • Part A 4-15 Unit A-4 • Introductionto Plant and Fire Safety Evaluating the risk associated with that fire hazard. This involves looking at everything from a fresh perspective of what could cause a fire. Consider the possibility of: ( a) Debris build up over time. b) The nature of the material in the location. c) Whether it is possible to move the material to a safer location. d) Occasional or temporary placement of hazardous materials in an area where they may not normally be present. e) The removal of barriers or protective methods that had previously been in place. Controlling the hazards may require solutions such as: a) Relocating the identified hazard to a safer area. b) Providing protection so that flammable material in the area can no longer come in contact with a heat or ignition source. Flammable debris must be regularly cleaned up. Replacement of guards and barriers may be necessary. Non-flammable materials can be substituted for flammable materials, where possible. Regular fire hazard inspections may be implemented. Individuals that work in the area may require training so that they can recognize fire hazards and prevent fires from happening. As well, they should be able to respond should a fire break out. GENERAL PROVISIONS PREVENTING A FIRE FROM OCCURRING There are numerous ways to prevent fires in a plant or industrial setting. These methods will be explained in the following paragraphs. ( Fire prevention practices include: a) Prohibiting smoking b) Allowing cooking only in prescribed areas c) Prohibiting fires and heat of any kind around combustible material It is also effective to have equipment in place that will automatically extinguish a fire, and having fire prevention equipment readily at hand to manually fight a fire if required. Housekeeping is very important for fire prevention. Keep all areas clean and free of a buildup of combustible materials. There are various conditions in which these materials can build up and become fire hazards. A schedule of regular inspections and cleaning, if necessary, should be implemented and monitored. Power Engineers may be required to do the sweeping and washing in a power house as it may not be safe for untrained personnel to come into the plant to do so. Work is to be considered incomplete until the debris created from the work has been cleaned up, especially if an area can become a fire hazard. 4-16 <(------------------------------4 -th_ _ C-Ia_s_ s _E_d-ibo _n_ _ 3_ • _P_a_ rl_A _ Plant Fire Safety • Chapter 4 ================================== == SPECIFIC POWER PLANT FIRE PREVENTION METHODS ( A Power Engineer will likely encounter fire hazards that those in other professions do not. Power Engineers burn fossil fuels as part of their normal operating duties. Power Engineers, then, must have special knowledge about safe storage, handling, and precautions when working with fuels. It requires extra diligence to make sure the only fire in the plant stays in the boiler furnace instead of spreading out to any surroundings - a particular concern for some solid fuel boilers. The following points cover fire prevention from the aspect of eliminating parts of the fire tetrahedron. Specifically discussed are removing: 1. Oxygen (air) 2. Fuel 3. Heat or ignition source Heat or Ignition Preventing possible heat sources from igniting combustibles can prevent fires. Process equipment, while operating, can create heat. Examples of sources of ignition are: a) Electric motors b) Steam lines c) Hot water or hot oil lines d) Tanks containing hot process material (_ For example, in a sawmill it is not uncommon for dust to accumulate on motor surfaces. Regular cleaning of the fins of a motor removes the insulating properties of the dust, and reduces the possibility of the motor overheating. In contrast, applying proper insulation to boilers, steam lines, and hot process tanks keeps the heat inside these tanks and lines, and protects employees from burns. Some sawmill boilers operate at steam temperatures hotter than the ignition point of paper. In this situation, insulation not only protects the workforce, but also prevents hot surfaces from contacting combustible material. Another example of an ignition source involves pulp mill boiler operation. A balanced draft boiler, such as a recovery or a hog fired boiler, can have blow-backs due to furnace pressure excursions. A blow-back will shoot burning fuel from ports in the boiler. Areas surrounding these ports should be constructed of fireproof material such as steel or cement, with no storage of flammable materials permitted. Control Ignition Sources There are two ways to control sources of ignition from heat: a) Keep the process equipment clean so that heat does not transfer to any combustible material that may be present. b) Contain the heat by insulating it from the rest of the equipment. If something can burn, then protect it with a protective non-flammable cover, where possible. Otherwise, separate the combustible material from any source of ignition, and store it in an area safely away from sources of ignition. Other ignition source prevention methods are outlined below. a) Clean chimneys and stacks. Inspect the chimneys, exhaust stacks, and ducting. Make sure that there is no buildup of combustible products, and clean the passages if necessary to prevent a fire from occurring. Ensure combustible materials are stored away from boiler chimneys and vent connectors. 4th Class Edition 3 • Part A 4-17 Unit A-4 • Introduction to Plant and Fire Safety b) Storage around heat sources. If possible, remove all combustible material and place it at a safe distance from the heat source. However, this may not always be possible. Consider a boiler fuel line; it must not have any lealdng gaskets, pacldng glands, and pipe joints. Oil drips can be caught in trays temporarily until the leak is identified and repaired. In some situations, temperature sensors, extinguishers, sprinlders, or fire insulating media may be installed. c) ( Identify hazardous areas with warning signs. Areas where workers may encounter flammable materials should be identified with warning signs that establish an area as having a possible fire risk. Often, these signs specify minimum safe distances for potential ignition sources (such as cigarette or cell phone use). d) Keep equipment clear of debris or other material. Do not permit material to pile up around heat sources, as it can cause overheating and potential ignition. e) Keep equipment that may overheat well ventilated. Equipment ventilation allows for air to cool off equipment that can overheat. In some locations, an HVAC system can be installed to maintain a lower temperature where equipment is prone to overheating. Other sources of ignition include: a) Static electricity that is discharged from material handling systems (such as plant vacuum hoses and fuel transfer stations). b) The use of electronic devices such as cell phones and two-way radios. When using hoses to transfer process materials in hazardous areas, or when transferring combustible products, hoses, pails and drip pans must be grounded to dissipate the static charge that may build up and cause a spark. Two-way radios and other electronic devices must be intrinsically safe when used in plants such as oil refineries and natural gas processing plants. Most cameras and cell phones are NOT intrinsically safe, and may create ignition sources. Therefore, these devices are usually prohibited at the worksite unless used under a hot-work permit. ( Hot Work Hot work is categorized as work done that creates hot conditions or sources of ignition. Hot work may include: a) Welding or brazing b) Flame cutting c) Use of a torch to heat frozen process lines d) Grinding e) Use of electric corded or cordless tools, such as drills or circular saws Hot work requires special procedures, and the assignment of specific responsibilities. A checldist should be created as part of the Field Hazard Assessment of the Safe Work Permit process to identify and remove possible fire conditions before starting any hot work. a) Check the area prior to start for possible hazardous conditions that can contribute to a fire. b) Remove any combustible material or debris away from the hot work area to a safe or safer area if possible. c) Provide barriers or non-flammable covers to protect materials and equipment that could potentially ignite. d) Wet down the area if possible to reduce the chance of ignition from sparks or welding spatter. e) Have a water hose and/or fire extinguisher present. Ensure that there is an individual present (this could be the worker doing the hot work) that is trained in fire extinguishing methods. 4-18 <(-------------------------------4-t_ h _C_Ias_s_E_d_itio_n_3• P _a _r_l_A ( Plant Fire Safety • Chapter 4 ================================ f) ( == Control or direct sparks or other potential heat sources that could cause ignition. g) Assign a Fire Watch to monitor the work for any potential fire creating conditions and respond if necessary. h) After the hot work is complete, the worker or assistant should review the work to ensure all ignition sources are eliminated. For example, any hot metal scraps left in the work zone can be cooled down and removed. i) Check the work area later in the shift after work is completed. In some plants, the Fire Watch must stand by for an hour or more after the work is complete, watching the area for signs of smoldering or of a potential fire. Electrical Equipment To prevent electrical equipment from becoming heat or ignition sources: a) Use only approved equipment rated for the work. b) Electric cords must be in good condition and rated for the conditions (moisture, oil, or abrasion resistant as needed). Use heavy-duty industrial cords that are built to withstand rough industrial use. c) Inspection of electrical cords should be done before and during use to ensure they are safe to use. d) In areas where pests can potentially damage equipment, pest control should be initiated to limit "wear" on electrical equipment. e) Avoid using extension cords if possible. f) Have defective equipment repaired or replaced promptly. Oxygen or Air ( Increased oxygen concentrations increase the possibility of a fire, or will accelerate a fire. An oxygen-enriched environment is described as having a percentage of oxygen in the atmosphere at or above 22 percent. Oxygen tanks and cylinders used in plants for flame cutting or medical purposes can create oxygen-enriched environments. Even compressed air from tanks or air lines may accelerate combustion. Therefore: a) Use caution with oxygen tanks- ensure fittings and connections are not leaking. b) Watch for oxygen enrichment activities such as chemical reactions that could generate excess oxygen. c) Increase ventilation to prevent buildup of oxygen enriched areas. Ensure forced air or induced air fans are operating, and other related equipment such as dampers and registers are operating or positioned properly. d) Never smoke in areas where oxygen is used or stored. e) Never use oil or grease on oxygen equipment, as oil and grease are more likely to ignite in contact with the high oxygen concentrations. f) Tanks containing combustible or pressurized media should be stored away from other buildings, and away from ignition sources. Oxygen tanks should not be stored near acetylene tanks or other flammable sources. g) Areas where oxygen concentrations may increase can be monitored with sensors and alarms. 4th Class Edition 3 • Part A 4-19 Unit A-4 • Introduction to Plant and Fire Safety ================== ================== Fuel Keep fuel - gases, liquids or solids - from burning anywhere except where intended. In order to do so, the following points will be discussed. ( a) Identify all combustibles. b) Store all combustibles properly. i. Do not store combustibles with heat emitting units nearby. ii. Store dry combustibles separately from flammable liquids, gases, and solids. iii. Store flammable liquids and gases in proper cabinets. c) Ensure that combustible materials used in the plant are properly stored. Gas cylinders not in use should be stored outdoors in an enclosure separate from the main building. Those in use in the plant should have two sets of chains holding the cylinder in place. Oil and grease should be stored away from other buildings in an enclosure properly equipped with fire prevention equipment rather than kept inside the power plant. Any grease or oil that is being used in the plant should be kept clear of all combustible conditions, and stored even temporarily in approved areas. Rags, papers, garbage, and other potentially combustible materials should be stored properly in approved areas. d) Transport all fuels properly. e) Areas that store waste wood material, grains, flour, or any other material that can create dust must be in a location that is physically isolated from any heat source, and insulated from any possibility of electrical sparks. These dusty areas can have dust suppression systems similar to those used handling coal. These are essentially large and powerful vacuum cleaning systems that collect and filter dust from where it may accumulate. Anything that can create piles of wood waste that build up over time, such as a buildup of debris under a conveyor, need to be swept or hosed away on a regular basis - especially any that can build up and rub against the belt and cause friction, or cover a bearing or motor and cause overheating. The cooling fins of motors should be cleaned of any dust that can build up over time. f) Sawdust and waste wood material from sawmills are a valuable fuel commodity, and are burned in "hog" boilers (wood that has been ground up or "hogged" and is suitable for burning). Hog fuel spills from conveyors and accumulates under the conveyor belts. Static discharge from the conveyor belts or overheated motors and bearings can ignite the fuel and cause disastrous conveyor belt fires. Regular use of a shovel or pitchfork or hose for cleanup and removal of these build-ups is necessary. g) Fuel line and equipment oil line leaks must be cleaned up and repaired as quicldy as possible. h) Coal dust must be removed from surfaces as it accumulates. Coal dust suppression systems must be in use whenever bunkering is active. Firing floors must be cleaned several times a day. i) Blowback from a solid fuel boiler can introduce combustible material to the areas surrounding the furnace ports. This material must be removed by hosing down the area and/or sweeping. j) Plants must be constantly monitored with both automatic fire detection equipment and with operators performing physical rounds. k) A schedule of regular inspections and cleaning should be implemented and monitored. 4-20 7------------------------- :s: 4th Class Edition 3 • Part A ( Unit A-4 • Introduction to Plant and Fire Safety FIRE PROTECTION STANDARDS, LAWS AND REGULATIONS Preventing fires is about preserving life as well as property. Buildings need to be constructed according to federal rules and regulations. In Canada, the National Fire Code and the National Building Code specify how buildings are to be constructed. They state the requirements for fire detection and suppression systems, based upon materials of construction and type of occupancy. Depending on the facility layout, its occupancy (industrial, commercial, residential, institutional, etc.), and its materials of construction, a facility will require various devices working together in order to promote fire safety. These devices may include: ( a) Fire zones and fire separation between zones, including fire doors and dampers. b) Smoke and fire detectors at specific locations. c) Sprinlders of specific types, at specific locations. d) Standpipes and fire pumps. e) Fire hose cabinets and extinguishers at specific locations. f) Smoke hatches. g) HVAC fan/fire alarm interlocks. h) Stairwell pressurization fans. i) Pull-stations. j) Alarm annunciation panels, horns, and lights. Please note the above list is not comprehensive. Provinces, territories, and often cities have similar regulations that are mostly consistent with federal regulations. They often reference the same supporting documents as federal regulations (or simply adopt the federal regulations as part of their regulations). These regulations take into account unique regional situations that may not be accounted for in the federal codes. Other codes such as the US National Fire Prevention Association (NFPA) codes are an excellent resource and are frequently referenced by Canadian laws or even adopted directly as law. 4-22 7 E S (