With the development of national economy in our country, the progress of the society and the improvement of people's living standards, clean room has been widely used in electronics, biological medicine, precision instrument manufacturing and so on all walks of life, because of the clean room in terms of temperature, relative humidity and cleanliness of a huge advantage, its importance is also more and more people know and accept. How to prevent fire accidents in clean rooms, we think that the key is to turn off the source of building fire prevention design, in order to eliminate the birth of congenital fire hazards. In this paper, how to do a good job in the clean room fire prevention design, talk about some opinions, for everyone to correct.
One, the basic characteristics of clean room
The so-called clean room refers to the workshop with special purification requirements on the building in the production process. Its basic characteristics are: 1, mostly reinforced concrete structure, plant separated for a number of small rooms; 2, often in a closed state, fewer Windows and fewer doors; 3, plant equipment is expensive, afraid of high temperature, avoid water; 4. The small number of staff in the factory is not conducive to the detection of fire and the handling of initial fire; 5. The internal structure is complex and the channel is tortuous.
Two, the fire characteristics of clean room
1, flue gas heat accumulation, spread way.
Clean rooms are generally in a closed state, with few doors and Windows. When there is a fire, the heat of the smoke is not easy to disperse outwards, causing the smoke to stay and the heat to increase. In addition, the ventilation pipes, electrical circuit bushings and technical interlayers in the factory are in collusion with each other, which is easy to cause the rapid spread of smoke and heat to other rooms.
2. Personnel escape is difficult.
Due to the requirements of the clean room process, the internal separation is complex, the channel is narrow and winding, the safety exit is few, the depth distance is long, the fire is easy to get lost after the occurrence of the fire, and the staff is few, the early fire is difficult to find in time, when the fireworks have been difficult to escape.
3. Smoke is highly toxic.
Some polymer synthetic materials are used in interior decoration. When these materials burn, they will produce a lot of smoke and emit poisonous gas, which will bring great threats to people's escape and fire fighting personnel.
4, large losses.
Clean rooms often have a lot of very precise and valuable equipment, and the construction investment is large. Once a fire occurs, the economic loss is huge.
In addition, some clean rooms now use methanol, acetone, toluene and other inflammable and explosive chemical dangerous goods in the production process, which pose a potential fire threat to clean rooms.
Three, the basic principles of clean room building fire prevention design should be grasped
According to the characteristics of the clean room and its fire characteristics, in order to protect the safety of people's lives and property, minimize the loss in the fire, and facilitate evacuation and rescue, we should follow the following principles in the building fire prevention design.
1, fire resistance rating and fire protection zone
From many cases of clean room fire, it is not difficult to find that it is necessary to strictly control the fire resistance grade of buildings. The fire resistance grade of the workshop is set as one or two in the design, so that the fire resistance performance of the building components is compatible with class A and B production workshops, thus greatly reducing the possibility of fire.
Limit the area between the firewall, set up fire partition, one is to control the spread of fire, reduce fire loss; The second is to facilitate the fire fighting, so that the fire personnel is easy to find the source of fire in the scene, but also easy to evacuate safely. Designers in the design should fully consider the characteristics of the clean room, strictly control the fire partition, make it meet the specification requirements, the current fire protection technical specifications have been put forward for clean room fire partition clear requirements, regulations, party a and b class production of clean room appropriate for single layer, its allowable building fire partition area, single-layer workshop appropriate for 3000 square meters, Multi-storey workshop should be 2000 square meters; The maximum allowable floor area of the fire protection zone of clean rooms of CLASS C, D and E shall comply with the provisions of the current Code for Fire Protection of Building Design. In addition, we should also pay special attention to the fire treatment of the ceiling and wall of the clean room, the partition between the clean production area and the general production area, and the technical shaft and other parts, requiring that it must use non-combustion material, and the fire resistance limit to meet the requirements of the corresponding technical specifications.
2. Safe evacuation
In view of the characteristics of the clean room itself, we should give full consideration to the requirements of safe evacuation in the design, comprehensively analyze the evacuation flow, evacuation route, evacuation distance and other factors, select the best evacuation route through scientific calculation, reasonably arrange the safety exit and evacuation channel, and establish a safe evacuation structure system. Make it meet the purification route from the production site to the safety exit without twists and turns. In addition, because the clean room is mostly in a closed state and the natural lighting condition is poor, fire accident lighting and emergency evacuation lighting must be set up in the factory building, and obvious evacuation indication signs should be set up at the corner of the safety exit, evacuation exit and evacuation channel so that personnel can recognize the direction and quickly evacuate the scene of the accident.
3, heating ventilation and smoke prevention and exhaust
Clean rooms are usually equipped with ventilation and air conditioning systems, which aim to ensure the air cleanliness of clean rooms in clean rooms, but it also brings a potential fire hazard. If the fire prevention treatment of ventilation and air conditioning system is improper, fireworks will spread through the ventilation and air conditioning pipe network, resulting in fire expansion. Therefore, in the design, we should set the fire valve reasonably at the appropriate part of the ventilation and air conditioning pipe network according to the requirements of the specification, and choose the pipe network material according to the requirements, and do the fire sealing work through the wall and floor of the pipe network, to prevent the fire from spreading with the ventilation and air conditioning system.
At the same time, because the clean room is relatively closed, it is not conducive to natural smoke exhaust. The accident smoke exhaust system should be set up in the workshop, and the mechanical smoke exhaust system with positive pressure air supply should be set up on the evacuation corridor to ensure that the smoke can be quickly discharged from the room and not invade into the evacuation corridor, so as to ensure that the personnel can evacuate the fire site safely in time.
4. Fire protection facilities
The clean room is equipped with fire water supply, fire extinguishing equipment and automatic fire alarm system according to the requirements of the code, mainly in order to find the fire in time and eliminate the fire accident in the initial stage. As the clean room has technical interlayer and lower interlayer for return air space, we should consider the arrangement of alarm probe, which is more conducive to timely detection of fire. At the same time, for a clean room with a large number of precision and expensive equipment, we can also introduce the early warning air sampling vesda alarm system, 3 to 4 hours earlier than conventional alarm alarm, greatly improving the fire detection ability, so as to achieve timely found that rapid processing, to reduce fire loss to the minimum requirements.
5. Decoration project
In clean room decoration, we must pay attention to the combustion performance of decoration materials and minimize the use of some polymer synthetic materials to avoid a lot of smoke when the fire occurs, which is not conducive to the escape of personnel. In addition, to do strict requirements on the electrical line pipe, in conditional places to use steel pipes as far as possible, to ensure that the electrical line does not become the way of fire spread.