“Explosions are a common cause of fires and a lot time and resources has been spent in coming up with the best ways of preventing an explosion ever happening. The following 4 techniques of ‘Structural Prevention’ involve constructing buildings in such a way that is specifically designed to prevent fires. They must also comply to the NCC (National Building Code) The techniques have been proven to effectively limit the risk of explosions and fires, helping save lives in an often subtle way”
The second effective technique is isolation. Isolation stops the explosion reaching other areas of the plant through pipes and ducts. It prevents the pressure from a primary explosion starting a secondary explosion and prevents the possibility of jets of flame issuing from long pipes. Depending upon the maximum explosion pressure, vessels may be constructed to contain the explosion. Most vessels that may be at risk of dust explosions are designed so that they will absorb the force of an explosion and not rupture.
The fourth technique is suppression. There are 3 ways to avoid creating an explosive dust cloud without modifying the dust itself:
• By adding inert gas to the atmosphere. This will reduce the amount of oxygen in the process area and thus reduce the chances of explosion
• By ensuring the dust is outside of its explosive (flammable) limits
• By adding inert dust, however this is not suitable for many industries as it contaminates the product.
The above 4 techniques are some of the main fundamental ways of preventing loss from fires right at the first stage of building an environment to live in or to work in. Designing a structure in such a way that helps prevent fires and helps limits the potential of loss during a fire is the best way of ensuring survival in the case of a fire emergency. Further information should also be sought to learn about the additional ways of preventing loss due to fire, to ensure that all eventualities are considered.
Yours in Fire Safety
The first technique to be described is ‘compartmentation’. Dividing a building into compartments or fire-tight cells using fire resistant materials can prevent the spread of fire and smoke within a building as well as the passage of vapour or dust clouds.
Fire compartment walls, floors and doors generally must provide a 60-minute resistance to fire, but this may vary depending upon the level of risk within the compartment. Walls, floors and doors subdividing such compartments generally must provide a 30-minute resistance.
Ceiling and floor voids as well as openings around pipe work and other services can allow air to feed a fire, as well as assisting in the spread of fire and smoke. Fire Stopping can be described as preventing the spread of smoke and flame by placing obstructions across air passageways.
The third technique is effective plant layout. Buildings that could be in danger of dust explosions must be designed along the same lines as any plant which has an explosion risk. The following features should be considered:
• Wherever possible, they should be isolated from other buildings
• Buildings should be preferably one storey high
• If inside, the vulnerable area of the building should be reinforced
• The rest of the areas of the plant must protected by a blast wall
• Sufficient venting to avoid structural damage from over pressure must be provided