Classification of places according to fire risk
We will examine the classification of fire risk in places so that we can calculate the amount of water with pressure and the appropriate duration for the sprinkler system according to each floor (class). Obviously, controlling and extinguishing fire in an office room is easier than in an oil and gasoline warehouse.
As with most important events in the sprinkler industry, this time insurance companies took the first step in classifying buildings by dividing them based on material value and vulnerability to fire. By the end of the 19th century, 584 different classes were designated by insurance companies. In 1932, this number decreased to 26 floors, but in 1946, it increased again to 100 floors, which were divided into 6 groups based on the type of building structure.
Today, NFPA 13 divides buildings into five different classes based on the flammability of materials present, the amount of flammable materials, the height of goods stored, and the rate of heat released, which differs from other building codes and even other NFPA codes.
This division consists of:
Office buildings, residential buildings and hospitals are included in this group. Extinguishing this class is easier than other classes and requires less water.
Extinguishing this class, which is also displayed as OH 1, is more difficult than the low-risk environment and includes places such as restaurants and parking lots.
Rubber factories and post offices are in this class (OH2).
Foundries and teahouses that use compounds with a flash point of less than 100 degrees Fahrenheit are placed in this class (EH 1).
Extinguishing this class (EH2) has the most difficult conditions compared to other classes, but it should be noted that if the amount of flammable liquids exceeds the permissible limit, then in the design of the sprinkler system, the conditions listed in NFPA 30 (Flammable and Combustible Liquids Code) should be used. Be considered. The place where flammable liquids are sprayed is classified as EH2.
This question may arise, if there is more than one risk class in a building, which class should the system be designed according to?
In response, it should be said that if the places can be physically separated from each other, then for each class we consider the rules related to the design of that class independently, but if they cannot be separated from each other physically, the design It is done based on the higher risk class.
It should be remembered that the maximum area covered by a sprinkler system on each floor is determined according to the risk class of the environment and its value is equal to:
More examples regarding the classification of places based on fire risk (taken from NFPA 13) are:
Low fire risk places include the following places or similar places:
Typical fire hazard spaces of group 1 include the following locations or similar locations:
Typical Group 2 fire hazard environments include the following locations or similar locations:
Group 1 high-risk environments include the following locations or similar locations:
Group 2 high-risk locations include the following locations or similar locations:
Source: Design and calculation book of sprinkler fire extinguishing systems