THINK 'PEDIH' REMEMBER 'PADiH'
This blog post is not intended to be 'too technical'. It meant to dis-mystify Fire Safety Design... Please don't even compare to the Red-Book. Remember, when you have fire, you may have smoke... the effect of smoke is that your eye feels - PEDIH, the Malay terms for 'burning sensation'... Yes, thus the simplest strategy to design for external fire safety is PADiH...
Foremost P stands for Planning... Just do the entire layout base on good old fashion site planning and positioning of your intended building blocks in whatever ways you want it to be. Ultimately to get it built it must conform to your Planning guidelines...
Then, consider A - Appliance Access. Fire Appliance is basically the Fire Engines - LAH... what else? Consider the requirement of access and design of the access road. Otherwise the truck will get 'stuck'...
Consider Di - Distance of Safety. Where the Fire Appliances going to park? How the fireman going to 'stage' their 'arsenals'? Ultimately, shoot water jets to fight fire from the surface...
Finally, consider - H for Hydrant Location... where to plant those hydrants, 90m apart?
Site Planning - Distance between buildings
Basically keep a safe distance between buildings so as not to allow, smoke to get over your neighbor's unit... Front to Front 80-60m, Front to Side 40m and Side to Side20m... Different authorities different guideline. This is not UBBL but under Planning Requirement.
This statutory requirement prescribed to you "how the fire engines gonna save your ass..." from the external... Yes, there is very 'little sense' on this but it is prescribed... Just follow. There are few critical comments on the effectiveness of this, but this is a 'broad approach' where your fireman is able to fight fire based upon the volume of your building... The bigger the volume, the bigger is the building and fireman has to reach all sides...
It goes dauntingly technical as to how one justify the 'safe distance' against the 'type'of fire engines... We are gonna skip this...
Just in case, the Fire engine needs to turn at 'high speed' as it may hits your building. The 'missing corner' is to allow for that...
You simply don't want the Fire Engine to get STUCK!
Safe Distance (not 'social distance')
Understand that Fireman's Life is also precious... They need to keep a safe distance too. Don't be too naive to think that they are gonna park their fire engine 'in front of the burning building'. No way. Burning debris may fall off the building and crumbling down. This zone is known as the collapsing zone. About 2-10m and please design for it. The access shall be around 6m. Yes, I know some author say, 4.5m is sufficient... remember, there may be car park along side? So, keep it 6m. This is to allow the fire man to adjust the space in between to fight high fire or low fire. Now, the fire appliance is 'technically a huge pump'. Yes, it pumps water from the nearest hydrant to replenish the fire tank in the building. This tank is connected to the internal fire fighting system. And remember the maximum it can goes from external is 18m.
Situation between a 'low-rise' with a 'high-rise'.
Safe Distance for Fire Appliance
Take note on the technical retirement ie.
How you shall design the 'fire fighting core' where fireman goes into the building against the 'protected core' for escape purposes. The 18m and 9m underground provisions are the max. standards.
Now, you can safely plant your hydrant at 90m apart... Just make sure that the 'circle' is overlapping just to keep the 'fireman' jolly.
End of Story for this Chapter. Please give us a LIKE if you find this INFORMATIVE.
You may have heard many abbreviation of 'safety concepts' from ASH to CEF... Although human lives are precious, in order to safe lives, one must first compartment the spread of fire to allow safe means of escape. Thus, compartmentalization comes first, follow by escape and finally, if permit, allowed fire fighting to happen in order to avoid further damages to the property. Fire fighting is indeed the last option available. This diagram allows cross referencing to the Uniform Building Bylaws UBBL.
Designing for fire safety in normal circumstances shall take that only one fire may start at one location at any one time. If multiple fires, it is already a natural disaster beyond the provision of the code. So, a 'blind test' must be given to your fire safety design if the fire starts here, where is the escape? Where are the compartmentalization? How to fight it?... It can or may start from anywhere within your design and you must have a solution to it.
The UBBL Schedules 5-10 are crucial in terms of designing for fire safety. It is a prescription of codes require one to comply. Notwithstanding compliance, one has perform a 'performance based approach' to validate what if such code could not be comply and what are the alternatives mean available under 'performance basis'... this involved modelling and computational requirement. Generally one must start from defining what are the purpose group. Different usage of the spaces required different groups. Then follows by limits of 'unprotected areas' whereas compartmentalization sets in. Next, consider how one would escape from one point to another and the notion of travel distance, crawling with smoke overhead to the nearest exit within a very specific time. Remember, it is supposed to be crawling, not running. The rest are related to appliances and fixtures to 'combat fire'.
How each activities and usage of space has been classified into purpose group by virtue of the matrix identifying the level of consciousness against the familiarity of the escape route and exit. Example, what would you reckon a kindergarten to be classified? A shop? A school? There should be no guessing games.
Generally all the purpose and usage of spaces shall fall squarely within these 8 categories but interestingly, car park podium is not clearly identified... The question is how do you assign occupancy load without knowing which is the category purpose group it falls within? Common sense tells you that car park is a storage for car, therefore under group VIII. Now, the mind boggling parts dictate that you can assumed that 2 person per car to be your occupancy loads. Alternatively, it has to be the same as per the space this car park services i.e. a cinema? Ambiguity in this area is there and some sort of clarifications are needed.
There is a science behind everything in fire safety design including the determination of how much time is taken to react... To understand this, one must understand the character of a combustion and its life cycle. Starts as an ignition and grow into a point of 'flash over', a sudden burst of flames that usually takes a third of the time of its entire life cycle. Half of these phases before reaching the flash over, is known as the 'untenable condition', an extremely critical moment for one to decide to fight or flight!
Zoom into this untenable phase, are a series of up scaling of temperature growth. Total evacuation must take place within two third of the untenable phase time, failing which the risks will multiply many folds. Reverse engineering, one third of the time must be taken as the process of evacuation. The alarm must be sound halves the time needed for evacuation and detection must kick in half the time needed for the alarm to sound. These are the basis of calculating the travel distance.
The UBBL 7th Schedule has provided you the limit. Yet, applying what is shown is beyond science but an art that they never teach you in school.
This chart identify as to how the travel distance and capacity exits are matched against the purpose group matrix.
In this given example, where alternative exit is available, you have 30m at both sides as your limit of travel distance. If sprinklers are provided, these distances are doubled. If only an exit is available in cases of 'dead end' you have obviously 20m max to reach your exit. Now, match against the UBL Schedule 7, would you able to see what they didn't teach you in school?
As a closure for this chapter, we will like to bring to your attention the human psychology towards selection of a means of escape. We tend to choose the familiar path, bright sides, open areas, open access and a transparent door way as our mean of escape. Therefore, it is important that design for fire safety must take such as an important criteria. Keep watch for next installation.
Credits: Significant amount of information presented here has been shared by Ar. Chong LeeSiong via his talks and webinars available in the internet.
Objective of this Page:
I am contributing to the public information regarding the application of Fire Codes in the Design for Fire Safety that has been the core competency of Architects, in general. These information is for educational purpose only and shall not be taken as an advice be it legal or otherwise. You should seek proper advice to your case with the relevant professionals. The author cannot guarantee the accuracy of the information so provided here.