Fire Protection Strategies in the Building - Case Study Example

FIRE PROTECTION STRATEGIES IN THE BUILDING Insert Name TABLE OF CONTENTS Introduction 1.0 Summary of the Building 1.1 Basement 1.2 First Floor 1.3 Second Floor 1.4 Third Level 2.0 Detection and Warning Systems 2.1 Basement Level 2.2 Ground Level 2.3 First Level 2.4 Second Level 2.5 Third Level 3.0 Means of Escape 3.1 Basement Level 3.2 Ground Floor 3.3 First Level 3.4 Second Level 3.5 Third Level 4.0 Internal Fire Spread Lining 4.1 Basement Level 4.2 Ground Level 4.3 First Level 4.4 Second Level 4.5 Third Level 5.0 Internal Fire Spread Structure 5.1 Basement Level 5.2 Ground Level 5.3 First Level 5.4 Second Level 5.5 Third Level 6.0 External Fire Spread 6.1 Basement Level 6.2 Ground Level 6.3 First Level 6.4 Second Level 6.5 Third Level 7.0 Fire fighting access and facilities for the fire services. 7.1 Basement Level 7.2 Ground Level 7.3 First Level 7.4 Second Level 7.5 Third Level References Introduction The objective of this report is to identify the various fire protection strategies within an academic building and assist in the building’s fire management processes. Towards the achievement of this objective, the author takes into consideration the various elements of the fire protection strategies that include: detection and warning systems means of escape Internal fire spread lining Internal fire spread structure External fire spread Access to fire-fighting equipment and fire services The analysis of these elements will enable the author to make recommendation to the building’s owner on the reliability of their fire protection strategy. 1.0 Summary of the Building The building under assessment is an academic building located in the middle of the city providing educational facilities to over 300 students daily. Occupants of the building include formal and non-formal staff, students, parents, visitors and suppliers of various products to the school. This high number of occupants necessitates the presence of adequate precautionary measures against fire and other disasters inherent to the building. The academic centre is a three-storey building with a basement and the ground floor whereby these floors are served by stairways and lifts. The building has three stairways and two lifts that serve the entire building. Notably, the basement is served by one lift due to the restricted access imposed upon the building’s occupants. On the other hand, the building’s corridors measure 4.1 metres and reduce to 2 metres around the stair number 1 area. Vent ducts, IT and electricity risers are present in all the three building’s floors. These risers ensure that common resources such as communication channels, air supply and electricity are availed in all the floors to enhance reliability. This also ensures that malfunctions within the established systems in a particular floor do not result into a halt in the entire building’s operations. 1.1 Basement The building’s basement houses the IT hub and switch room that require restricted access to enhance reliable service provision within the entire building. A high level vent duct and riser are present within the basement to ensure adequate air flow within the basement. Other facilities within the basement include the stores, changing room for the catering staff and a 110-seater lecture theatre. The building’s ground floor houses several administration offices that include two counselling offices, the head of student services office, the academic and student services office and the reception. Other facilities include group kitchen, workspaces, the furniture and recycle stores as well as the dining areas. 1.2 First Floor On the first floor, the building houses the principal’s and admission’s offices that are located at the extreme left of the building. This floor has four classrooms, three IT/language and computer labs. The sitting capacity for classrooms on the first level is 86 students and hence the need to make the stairways accessible from all classrooms. 1.3 Second Floor On the second floor, the centre houses the staffroom and preparation area, the examinations store and an administration office. Other facilities include the counselling office, five classrooms with a total capacity of 102 students, an 80-seater lecture room, a language/IT lab and the centre’s library. 1.4 Third Level On the third floor, the centre has the main staffroom, two teaching offices, a preparation room, one multimedia lab, a science lab, a 36-seater classroom, the air handling plant, an 80-seater lecture room and a study area. Additionally, this floor has a roof access that allows access to the rooftop when need arises and especially during emergency evacuations or assistance. 2.0 Detection and Warning Systems Section 1 of Approved Document B provides for the installation of fire alarms and detection systems within buildings using a standard arrangement. The standard arrangement arises from the distance to be travelled to access the fire alarm triggers during an evacuation process. 2.1 Basement Level The building’s basement is halfway utilised with a single lecture room and several stores as well as the IT hub. From the basement’s layout, the basement can be accessed via two stairways and a single lift. During fire disasters, individuals are exceptionally required to utilise the lifts however, majority will utilise the stairways. Thus fire alarm triggers ought to be placed near the stairways when they are highly accessible. Paragraph 1.14a states that fire alarm triggers and smoke detectors should be placed every 7.5m along the main corridors serving the level. Paragraph 1.17 states that smoke detectors should be placed near air-conditioning outlets to prevent false alarms (Communities & Local Govt. 2000, p19). 2.2 Ground Level Unlike in the basement level, the ground level is served by three stairways and two elevators that are fully functional. However, fire alarm triggers and smoke detectors should be placed every 7.5m across the levels main corridors. The ground level houses the building’s kitchen and careful consideration ought to be given towards the installation of fire detectors within the kitchen unit. Paragraph 1.17 states that the high temperatures could create air currents that drift away the smoke hence being undetected (Communities & Local Govt. 2000, p19). 2.3 First Level Paragraph 1.19 specifies that smoke alarms and fire-alarm triggers should source their power from the building’s main supply unit. This ensures constant power supply within the building and avoids disconnections over prolonged periods. However, power supply to the fire alarms and smoke detectors should be easily isolated without interfering with the building’s lighting (Communities & Local Govt. 2000, p19). 2.4 Second Level As provided for in paragraph 1.29, fire alarms ought to be audible and should be electrically operated whereby the electrical installations are guided by Approved Document B. The fire warning system should comprise of manual call points that are established directly adjacent to the room exits. Due to the high number of occupants at the second level, public address systems should provide an audible signal to avoid commotions during the alarm response period as provided for in clause 1.32 of the Approved Document B (Communities & Local Govt. 2000, p20). 2.5 Third Level With the multi-media lab being located in the third floor, it might be impossible for the students to hear the fire alarms. Clause 1.34 provides that both visual and audible fire signals should be installed for example the vibrating paging system (Communities & Local Govt. 2000, p20). From the site plan, fire alarms should be placed at points 1, 2,3,4,5, 6 and 7 along the main corridor as well as at points B and C across the main corridor. One alarm should be placed at the farthest but opposite sides of the main corridor. This should be done for the ground, first, second and third levels of the building. For the basement level, a total of 3 alarms should be placed at points 5 and 6 as well as at point B on the right hand side of the building. (See attached site map 1.0) 3.0 Means of Escape According to the UK building regulations, buildings ought to have sufficient escape routes that have the capacity to enable all the building’s occupants to escape to safety in the event of a fire disaster. Escape routes within buildings should be suitably located to enhance access and usability during times of emergencies. 3.1 Basement Level Accessing the final exit from the building’s basement is quite difficult since the occupants have to access the ground floor. The stairways through which the basement is accessible may be filled with smoke hence the need to construct a protected stairway leading to the final exit as provided for by clause 2.6. Due to the significant number of occupants in the basement level, external windows and doors ought to be provided for egress from the basement level. According to clause 2.9, egress windows and external doors should have a protected minimum area of 0.33m2 as well as a maximum height of 1100m above the floor. The maximum travel distance should be 18m for the occupants to access the exit at this level (Communities & Local Govt. 2000, p23). 3.2 Ground Floor With a height not exceeding 4.5m, fire escapes on the ground level should comprise of direct exits in form of windows and doors leading to the final exit as provided for by clause 2.11. These exits should comply with the requirements of the Approved Document K and should be fitted with locks (Communities & Local Govt. 2000, p23). Alternatively, except for the kitchen, all other units should have access doors between them to serve as entrances to other units to facilitate escape. Diagram 23 indicates that the minimum travel distance towards the exits on the ground level should be 27m (Communities & Local Govt. 2000, p51). 3.3 First Level According to clause 2.12, units at the first level should comprise of an egress window and external door that complies with the requirements of clause 2.9 of the Approved Document B. These facilities enable the occupants move from one unit to another to access the final exit. However, this level ought to have an internal protected stairway that leads to the final exit. Occupants of the various units within the building ought not to cover more than 9m to access the unit’s entrance or exit facilities. Clause 4.15 specifies that the minimum widths for the escape stairs should be 1400mm if their vertical length is more than 30m (Communities & Local Govt. 2000, p46). 3.4 Second Level Due to the level’s height above the ground, units on this level ought to have alternative door exits that have direct access to common stairs, external stairs or an escape route over the roof. The level’s occupants should not travel more than 7.5m to access the three protected stairways serving the level. This seeks to reduce the exposure risk to the toxic fire fumes before accessing the stairways and eventually the final exit. As stated in Communities & Local Government clause 4.7 provides that refuges be installed along the stairways to aid the disabled in accessing the final exits to the exterior of the building (2000, p44). 3.5 Third Level Due to its light weight, smoke raises upwards hence its capability of filling the stairways. To facilitate escape, vents should be provided along the stairways and corridors adjoining the stairways according to clause 2.26. The vent should have a free area of 1.5m2 and located on the external wall. Vertical smoke shafts should have a cross-sectional area of 1.5m2 with an roof opening of 0.5m above the roof level and should be constructed of fire and smoke resistant material. Due to the accessibility to the building’s roof, the design of this accessibility ought to comply with the requirements of paragraph 5.35. Table 5 specifies that the maximum distance of travel towards a fire exit should be 45m (Communities & Local Govt. 2000, p58). Room/Area Primary Escape Route Approx. Travel Dist.1 Secondary Escape Route(s)2 Approx. Travel Dist.1 Basement Level Lecture Theatre Main Stairways 28 metres Lobby 0.03 on the west wing 14 metres Stores Main Stairways 9 metres None due to their proximity to the stairways 19 metres Catering Changing Rooms and Office Main Stairways 7.4 metres At the back of the office 17.4 metres Ground Level Kitchen Main Stairways 4 metres It is not enclosed hence providing adequate escape space. 18.6 metres Academic Service Offices Main Stairways 21.5 metres The second main entrance 16 metres First Level Main Stairways 11 metres 11 metres Classrooms Main Stairways 14.8 metres The door at the back of each classroom 27.3 metres Language IT Labs Main Stairways 8.5 metres The door at the back of each lab that leads to the next lab 18.8 metres Open Plan/Principal Office Main Stairways 5 metres None 18.8 metres Second Level Library Main Stairways 5 Metres Compartment doors 8 Metres Counselling Offices Main Stairways 10.2 Metres Compartment doors 20.8 Metres Third Level Lecture Room 402 Main Stairways 2 Metres Back entrance 8 Metres Air Handling Plant Main Stairways 10Metres Back exit 4 Metres Staff Work Room Main Stairways 12 Metres Back Exit 6 Metres Note: There may be other alternative escape routes for each of the rooms; however, these secondary routes were chosen to minimise the travel through the building, maintain the straightest path, or both. 3.6 Calculations A. Types of space in m2/person a) Office: 6m2/person b) Kitchen: 7.0m2/person c) Queuing area: 0.7m2/person B. Floor area and occupancy limits 1. Office: 180m2/6m2 = 30 persons 2. Kitchen: 1423m2/7m2 = 203 persons 3. Queuing area: 76.1m2/0.7m2 = 108 persons Note: Space specifications as provided Table C1 Floor Space Factors, Approved Document B (Communities & Local Govt. 2000, p135). 4.0 Internal Fire Spread Lining Internal linings within buildings include ceilings and walls that are lined with incombustible material with the capacity to inhibit the spread of fire within a level’s units. Clause 6.2 specifies that wall linings include the glazing surface and parts of the ceiling that slope at more than a 70-degree angle to the horizontal (Communities & Local Govt. 2000, p64). Doors and their frames, windows and their frames as well as the fitted furniture are not considered as part of the wall. Fire disasters within buildings can be contained through walls and ceiling linings that have the capacity to control the spread of the fire. This can be achieved by ensuring the right choice of structural material for the construction of the building’s walls and ceilings (Lennon, T & Building Research Est. 2004, p69). It should be noted that, as a multi-storey building, the academic centre’s ceilings are floors for the next level. 4.1 Basement Level The basement’s ceiling is the floor to the occupants of the ground level. To prevent the fire from spreading to the ground level through the ceiling, suspended ceilings should be constructed. The construction of these ceiling linings should conform to the specifications provided in Table 10. This is basically because of the reduced movements in the basement and the low number of occupants at any given time relative to the overall occupants. For the various units occupying the basement, the walls should be constructed using thermoplastic material to prevent the spread of fire within the basement level as provided for in clause 6.10 (Communities & Local Govt. 2000, p64). 4.2 Ground Level Ceilings and walls at the ground level should be adequately reinforced to withstand high heat conditions as they provide the main exit from the building. During fire evacuations, all the occupants will be directed to the ground floor for them to exit the building. Resultantly, the various units in this level should be constructed in such a way that they can withstand intense fires for a minimum period of 30 minutes (Lennon, T & Building Research Est. 2004, p37). 4.3 First Level The various elements of the structure at the first level include structural frames, floors and load bearing capacity walls that have sufficient capacity to withstand the building’s weight load. The construction of the fire-resisting ceiling complements the cavity barriers in the second level (International Code Council 2003, p91). 4.4 Second Level Fire resistant ceilings and cavity barriers in this level’s floor prevent the spread of fire to other parts of the building. Fire resistant ceilings should be lined with thermoplastic material to prevent excess heat from the fire weakening the building’s structural material. However, ceilings might enhance the spread of fire once they become combustible. International Code Council states that the diffusers ought to be used to slow down the spread of fire to other parts of the building (2003, p103). Additionally, the compartmental walls should be constructed using fire resistant material to prevent the spread of fire within the level’s compartments. 4.4 Third Level The roof at this level may comprise of lighting diffusers that can be placed anywhere except above the stairways and classrooms. Clause 6.13 specifies that the lighting diffusers should be 5m2 each separated with a minimum interval space of 3m to ensure sufficient light into the building (Communities & Local Govt. 2000, p65). Table 11 provides guidelines towards the application to thermoplastic roof lights and lighting diffusers in suspended ceilings that constitute the ceiling linings. 5.0 Internal Fire Spread Structure Due to the weight associated with multi-storey buildings, the collapse of the structure during fire disasters can be avoided by ensuring that the structure’s load bearing elements attain the minimum standards of fire resistance. From clause 7.1, this seeks to reduce the level of risk the building’s occupants, individuals in the building’s vicinity are exposed to as well as that of the fire response teams. 5.1 Basement Level Columns and pillars in the basement level provides the basic building’s support structure hence their fire-resistant construction should be greater than that of similar structures in other levels as stipulated by clause 7.3. Compartment walls between the various units in the basement level should comply with the load bearing elements as provided by clause 7.5 (Communities & Local Govt. 2000, p69). According to section 8.20, compartment walls ought to contain fires in the various units they separate. According to clause 8.14 of the Approved Document, buildings with more than one storey should be fitted with sprinkler systems to reduce the impact of the fire (Communities & Local Govt. 2000, p72). 5.2 Ground Level A compartment floor ought to be constructed beneath all units within this level as specified by clause 8.18(c). Compartments within this level should have a maximum measurement of 4000m2 where sprinkler systems have been installed as indicated in table 12. Clause 8.21 provides that compartment walls should measure the level’s height and width in a continuous vertical plane (Communities & Local Govt. 2000, p74). 5.3 First Level Due to the many units in this level, compartment walls and floors are bound to intersect at a junction. According to clause 8.25, the junction should be able to uphold the fire resistance of the compartment (Communities & Local Govt. 2000, p75). Notably, clause 8.32 (a) specifies that openings in compartment walls should be limited to egress doors and windows that meet the required fire resistance standards. Pipes passing through the compartment walls should be made of non-combustible material and should not measure more than 160mm in diameter as provided for in table 14. 5.4 Second Level Concealed spaces within the building’s structure have the capacity to fuel the spread of smoke and fire within compartments. This on the other hand, reduces the structure’s strength hence increasing its chances of subduing to a fire disaster. At this level, cavity barriers should be provided at the internal/external cavity wall and compartment floor/wall junction as provided by clause 9.3 (a) and (b). Clause 9.7 specifies that cavities below or above wall partitions should be fitted with cavity barriers in line with the partitions. The construction of cavity barriers should be able to provide at least 30-minutes fire resistance without subduing to the fire as provided by clause 9.13 (Communities & Local Govt. 2000, p84). The cavity barriers should be constructed of at least 0.5mm thick steel, 38mm thick timber or polythene-sleeved mineral wool (British Standards 2008, p178). 5.5 Third Level As the building’s top-most level, the level’s roof structure comprise of timber trusses that bridge the compartment walls. This poses a fire threat to other compartments as fire can easily spread through the roof structure. To prevent this, clause 8.20 provides that trusses should be designed in such a way that the collapse of part of the truss in one compartment does not result into failure of the truss in another compartment. Additionally, compartment walls on this level should continue through the roof space for a minimum of 375mm (British Standards 2008, p150) 6.0 External Fire Spread The external fire spread structure seeks to reduce the spread of fire among the buildings present at a single location through the various structure components such as the roof. Towards achieving this objective, the building’s height and position should be considered to determine the best alternative in preventing the spread of fire to another building. Section B4.i states that the ability of the external walls to contain the fire depends on the distance between the buildings and the size and intensity of the fire (Communities & Local Govt. 2000, p91). 6.1 Basement Level Basically, the basement level does not have the capability to spread fire since it is sunk into the ground. However, the external walls of the building should be constructed to comply with the fire resistance standards provided in table A1 as stipulated by clause 12.3 (Communities & Local Govt. 2000, p93). Due to the positioning of the basement level, the external wall has the capacity to reduce the heat intensity generated from the fire or radiation that passes through it. 6.2 Ground Level This level’s external wall should be constructed at least at a distance of 1000mm from the relevant boundary. However, this space could be reduced by the interior of the external wall should be lined with fire resistant material to reduce the fire intensity. Diagram 40 provides that the 1m boundary distance is limited to a building not over 18m in height. Section 13.2 provides several assumption towards space separation that include the effect of the building’s division into compartment on the size of the fire, purpose of the building and the ability to discount the amount of radiation that passes through any segment of the external wall (Communities & Local Govt. 2000, p96). 6.3 First Level Parts of this level that have reduced fire resistance comparative to the standard level are referred to as an unprotected area. Section 13.9 provides that any section of the external wall that has combustible material over 1mm thick is to be regarded as an unprotected area. The edges of canopies situated in this level should be at least 2m from the relevant boundary as stipulated by section 13.11. 6.4 Second Level Along the building’s external wall, some un-protected areas may be disregarded during the separation distance from the boundary assessment exercise. However, the disregarding of the unprotected areas should be guided by diagram 44 whereby the minimum distance between unprotected areas is 4000mm in all directions excluding where compartment walls and floors separate the two unprotected areas. In such instances, a minimum distance of 1500mm should be observed and all the unprotected areas should have a maximum measurement of 1m2. Unprotected areas on the exterior of a protected stairway could also be disregarded during the separation distance exercise (British Standards 2000, p199). 6.5 Third Level Roof structures on the third level ought to comply with section 14 of the Approved Document B. Roof coverings near boundaries provide escape routes as identified in clause 5.3. As earlier indicated, diagram 47 depicts the spread of roof lights on the building’s roof structure. Plastic roof lights should at least attain the Class 3 or Class D-s3 standards to guarantee their capability to prevent the spread of fire through the roof structure. Such roof coverings should be placed at a minimum distance of 6m to 20m from any point on the relevant boundary. These measurements are provided for roof lights covering the balcony, veranda and other compartments with a maximum area of 40m2 as indicated in Table 16 (Communities & Local Govt. 2000, p103). 7.0 Fire fighting access and facilities for the fire services. During construction, facilities should be provided to assist fire fighters in accessing the building during times of fire disasters. 7.1 Basement Level According to section clause 17.1, fire fighters require special access to the building’s basement equipped with fire mains. The fire fighters have to access the basement within proximity of the mains for their appliances. Smoke from fires tends to rise upwards through the stairway hence inhibiting access to the basement level (British Standards 2000, p122). Section B5.ii (e) provides that vents could reduce the levels of smoke along the stairways thus enhancing access to the basement level. Clause 15.8 provides that alternative sources of water supply for the water mains should be sought in instances where there is no stable water supply or insufficient pressure to pump the water. 7.2 Ground Level Section 16 provides for vehicle access to the building’s main compound on which the ground level is located. This provides a base for high-reach appliances to be utilised and enable pumping equipment to supply water. According to Clause 16.2, there should be access routes for vehicles within every 45m interval across the building’s perimeter. From diagram 49, the maximum distance between the building and the edge of hard-standing from building should be 4900mm for the turntable ladder and 2000mm for the hydraulic platform appliances. The maximum width for the appliances should measure between 5m to 5.5m to enhance access to the top levels. Section 16.11 specifies that fire rescue services should not reverse more than 20m from the end of an access route (Communities & Local Govt. 2000, p108). 7.3 First Level The first level is within the reach of the fire fighting vehicles and the fire rescuers can easily access the floor with assistance from the rescue vehicles. However, clause 17.1 provides for the establishment of fire fighting lobbies to aid the fire fighters in their tasks. 7.4 Second Level Section 17 provides for the construction of fire fighting shafts through which the fire fighters access the building’s interior. Fire fighting shafts ought to comply with the laid out specifications in clause 17.13. Clause 17.11 specifies that the fire fighting lobby should be approached from the accommodation through a fire fighting lobby (Communities & Local Govt. 2000, p112). Additionally, all fire fighting shafts should be installed with fire mains that have an outlet within the level. 7.5 Third Level This level requires the availability of fire fighting shafts especially in the form of fire fighting lifts to enhance access to this level. This includes the lift car, well and machinery space in addition to the lift control and communication systems. From diagram 52, the fire fighting shaft should be constructed to withstand the effects from fires for 2 hours (Communities & Local Govt. 2000, p114). References Communities & Local Govt. 2000, The Building Regulations 2000: Fire Safety; Approved Document B. British Standards 2008, Code of Practice for Fire Safety in the Design, Mgmt & Use of Buildings. International Code Council 2003, International Building Code 2003, 2nd Ed, Michigan: Univ. of Michigan. Lennon, T & Building Research Est. 2004, Structural Fire Engineering Design: Materials Behaviour, New Jersey: BRE Bkshp. Read More