CATEGORY HOPPING
M
L4 L5
L3 L2 L1
P1 P2
The importance of system categories as laid out in SANS 10139 are often ignored, or not understood.
Before one even opens the drawings or the specification, we have to select the category we are going to design to.
We have to understand the reason one wants a fire system installed in the first place. Do we need to protect the people in the building by giving an early warning for them to evacuate safely or maybe to provide a warning that there is a fire in an area that may damage assets or equipment, or we may need to open smoke vents.
This has to be followed by understanding the environment in the areas we are protecting. Is it dusty, is there high wind movement, are there cold rooms or freezers in place, do people sleep in the building or is it normal office conditions.
With this information under our hat we can then decide which category is suitable and start the design effort.
Who decides upon the category?
This decision should be reached between the fire detection system designer and the customer. The categories are explained to the client so he is fully in the picture as to what your design will provide him with.
This decision can also be made or influenced by the insurer or the fire department.
Remember it will always be the fire detection system designer who will carry the responsibility for what he puts on paper.
Once the category has been decided the customer, installer, commissioner, supplier, inspector, insurance company and fire department are then all aware of the type and purpose of the fire detection system installed.
As inspectors we often arrive on site and find there is no information as to what category was used as the basis for the design. Are there detectors in all the offices or just some parts of the building? the installer normally says, “it is to a consultant’s design”.
When a report is produced when defaulting the inspection to an L1 category, the complaints start.
Nicknamed: "Category Hopping"
Inspector – “We inspected to an L1”
Contractor – “No but I think it was a P2”
Inspector – “But the installation does not comply to a P2”
Contractor – “Oh, OK let’s make it an M”
It becomes obvious this system was installed with no thought, no purpose and lacks professionalism.
By following the proper design process, by starting with the category, life is made easier for everyone at all levels of the project and for the life of the fire detection system thereafter.