Sunday, February 28, 2010

Substation fire protection system

All electrical substations and main switchrooms need to be provided with a fire protection system. This post try to provide beginners with some  pictures to help them grasp a minimum degree of basic understanding on fire protection systems for electrical substations.

Picture a1 - Electrical substation CO2 cylinder tanks
(Click on the picture to enlarge it)

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If an electrical substation building is designed and constructed as a separate building, the provision of portable fire extinguishers as the sole form of fire protection may be accepted by authorities as adequate.

It is quite common for some local offices of the electricity supply authority and local offices of the Fire Department to follow this practise.

However, major substation rooms that are part of an occupied building are usually required to have some form of an automatic fire extinguishing system such as a CO2 system, or a clean agent fire extinguishing system.

Picture 1 – CO2 fire protection cylinders being installed


The above picture shows a CO2 automatic fire extinguishing system being installed inside a standby generator room under construction.

When I wrote this post, the building was still under construction. So the standby generator room was not yet fully completed.

What system to use
What fire protection system to be used for a substation depends on the preference of the design consultants, and the minimum requirements of the local Fire Authorities.

If the substation room involved is also to be handed over to the electric supply authority, then the minimum requirements and preferences of the local office of the electric supply authority should also be taken into account.

The fire authorities usually have an already established requirement of what system is required in a substation room.

The engineering consultant's design engineers usually prepare their initial designs based on these requirements.

These initial designs are then coordinated with the main building design which usually is the territory of the design architect for the building project.

Here I am talking about electrical substations and other electrical rooms of a building project.

Electrical substation buildings that belong to the electricity supply authorities' distribution network is a different matter altogether with regard to fire protection systems. This post does not cover those substations.

After completion of the initial design, the project's design architect then submits a number of sets of relevant architectural design drawings to a number of authorities and local municipalities for review and approval.

The local Fire Authority is also part of the list that requires drawings submission from the building design architect.

These are the drawings of "passive fire protection". Detail explanation of passive fire protection may drag me off the topic of substation fire protection too far.

So I will do that in some other separate post.

Lets just say for now that a passive fire protection is a design of the buildings' overall layout and their building components with respect to danger to human lives and properties in the event of a fire.

This involves among other things how the building layout is designed to allow occupants of the building to escape quickly and safely during fire;
how a fire that started in one part of the building is prevented from spreading to other part of the building;
how is the layout designed to allow and help the fire fighters fight fires;
how many hours the related building components (i.e. fire doors) can prevail during fire; and so on.

Related to this also is the emergency lighting system that is needed by the occupants in the event of a fire so that they can see the escape paths; also the "EXIT" signs that are supposed to guide them to exit the building or to designated "fire-free" areas.

These are among the details on the drawings submitted by the architect to the local Fire Authority.

These details are called static fire protection.

The "active" fire protection systems are not submitted yet to the Fire Authority.

As I just said, the building layouts are designed by the Architect with the help of engineers which include civil and structural engineers, and also the mechanical and electrical engineers.

The "active" part of the fire protection system is the part that actually monitors, detects, and extinguishes fires.

Also the parts that involve pumps and piping that would be used by the firemen (or anyone for that matter) to fight fire.

Included here also are the communication system that can be used during a fire situation, which include a public address and announcement system, and firemen intercom system.

This is the part that is designed by mechanical and electrical engineers.

It therefore follows that the submission of the active fire protection to the Fire Department should be done by the mechanical and electrical engineers.

So after the submission of the passive fire protection system has been approved by the fire authority, the submission of the active fire protection commences.

This submission is done by the mechanical and electrical design engineers (also called "MEP engineers" in some part of the world).

The process of reviewing and commenting on the drawings submission by the fire authority may take one to three months to complete.

However, once the passive fire protection drawings have been approved, then the actual construction works of the buildings (including the substation buildings if it is separate from the main buildings) can commence.

What is an active fire protection system?

The CO2 system in Picture 1 above is one example.

This system monitors all rooms in the substation for signs of fire. It triggers an alarm if signs of a fire are detected, either in the form of heat or smoke.

If the signs of smoke meet a certain design criteria, the "fire fighting system" is triggered to extinguish the fire.

This is an over-simplified description of a fire fighting system.

However it should be enough to give beginners an initial understanding of how a fire fighting system in substations and electrical rooms work.

Below are a few more pictures of the fire protection system for the electrical substation rooms in the same project as Picture 1 above.

I also give very brief descriptions of how it works here.

At the end of this post, I attach more pictures on fire protection with a brief description for each picture.

Likewise, over time I will keep adding more pictures at the bottom of this post. In this way I can give you pieces of information on this topic without the burden of having to write a new article for each new photo.

This may also help to minimize the number of post titles that I need to write on fire protection systems.

I do not wish to confuse Google's search engine into thinking that this blog is also a blog on fire protection system, which is a topic  under mechanical, not electrical.

Picture 2 – Weatherproof CO2 panel


(Click on the picture to enlarge it)

Picture 2 above shows the CO2 control panel outside a transformer room at the same building as Picture 1.

A CO2 control panel usually acts as an independent local fire control panel.

In a large building or complex, the local fire panel is connected to a Main Fire Control Panel of the building complex.

The main fire control panel is usually located in the building's Main Control Room and is usually manned by employees assigned by the building management.

Some of the alarm signals and indications on the local fire panel (the CO2 control panel in this case) are repeated at the main fire control panel.

Observe the components of the automatic fire fighting system that are visible in Picture 2.

The alarm bell is self-explanatory.

It is selected to produce an audible alarm ringing of at least 5 dBA above the ambient noise or a minimum of 65 dBA, whichever is greater.

This is a common design criteria.

The ringing sound should be the trembling type, not the single stroke sound, and it should be sustained for a minimum period of 30 seconds.

The bell must operate from the fire alarm battery and any fault on the bell circuit should not have any effect on the transmission of the fire signal to the main fire control room or to the Fire Department's monitoring station.

Automatic detection of fires

The automatic detection of a fire inside a substation room or an electrical switchroom can be done by either by a smoke detector or heat detector.

The usual practice is usually by a combination of both.

The system inside Picture 2 above used two smoke detectors and two heat detectors.

This is a common practice for individual electrical room spaces such as transformer rooms or small switchgear rooms.

If a room is large, more detectors may be required depending on the the room's actual size.

Picture 3 – FM 200 fire extinguishing system



The CO2 system has been a widely used type of fire extinguishing system since I can remember. However it is now being slowly phased out. The reason being the gas is highly lethal.

There have been a considerable number of fatality cases due to the system discharged by accident while workers were still working inside the substation room.

Picture 3 above is one of the alternatives to the CO2 system. This one is called FM 200 and this picture was taken while the installation is progress for a server room in an office building.

Picture 4 - Portable fire extinguisher inside a 33kV substation
(Click to enlarge the picture)

Observer the elaborate markings of the location of the portable extinguisher: the painted marking on the wall and floor, the signage and the extinguisher numbering on the wall.

This is a clear statement of how important the portable extinguishers are in a 33kV substation, and how important it is to have them provided with markings that stand out.

During the starting moments of a fire incident, every second counts. It is therefore extremely important for the personnel inside the substation to be able to locate the extinguishers quickly.

Picture 4a - A close up view of the portable extinguisher

Picture 4b - A portable extinguisher outside the construction site office of a building project



Picture 5 – Mounting hook for a portable fire extinguisher


This is the end of this post.

Below you can find more pictures of fire protection systems for electrical substations.

In future I will keep adding more of similar pictures at the bottom,  not just for electrical substations but for other areas of buildings also.

xxx ADDITIONAL PICTURES XXX

Picture 06 - Main control panel and firemen intercom master panel at Fire Control Room

(Click on the picture to enlarge it)

The above picture shows part of the equipment installation in progress in Fire Control Room of a building complex.

As I briefly explained at the beginning of this post, when the substation is part of a building complex, all fire fighting control and monitoring systems at each

mechanical and electrical plant rooms, including at electrical substation rooms, are connected to a central fire control panel of the building complex.

What you can see in Picture 06 are the Main Fire control Panel and the Fireman Intercom Master Panel.

I labelled also where the master panel's mimic diagram is. Of course you cannot see the mimic diagram there.

The glass window of the mimic panel was covered with a thick cardboard to give it some degree of protection during the installation.

This picture was taken during the last phase of the building construction. As usually is the case, this was the period when all equipment inside the Fire Control Room

would be delivered to the room, fixed to their designated location, wiring works connected the equipment, tested and and commissioned.

Many parties are involved here during this period.

Besides the master panels that you see in the picture, there are others also in the same room: Lift control and monitoring panel, Building Control System master panel,

Public Announcement and Firemen Emergency Announcement Master Panel, and Closed Circuit Security Camera (CCTV) Master Panel.

All of these in the same room.

Why? Because this is generally where the 24 hour central security station would be located.

I said generally because the precise arrangement varies depending on the management team responsible for the building.

First point of contact for firemen during fire

In the event of an actual fire, this is where the firemen team would come first when they arrive at the scene afer report of a fire.

Even when the fire is at a substation which is in a separate building beside the main building complex.

Arrangement of location of the Main Fire Control Room is an interesting topic of its own. Maybe I will consider a sending a separate post just for it.

The Firemen Intercom Master Panel

In a large building complex, fighting fire is an extremely high risk job.

Firemen need to enter the building under the thick of fires, smokes and falling objects.

The firemen need a reliable communication facilities to talk to the fire chief commanding the fire fighting and rescue operation.

The firemen intercom is for that purpose.

At each landing of a fire escape staircase, one unit of the intercom console is provided and it is wired via a fire resistant telecommunication cable to a master

panel similar to one in Picture 06 above.

Even the fire intercom consoles inside our electrical substation are also connected and monitored from this master panel inside the Fire Control Room.

The more consoles that are installed in a building complex, the bigger the dimensions of the master panel would be.

Picture 07 - Firemen Intercom Master Panel

(Click on the picture to enlarge it)

This is a photo from another picture shot.

As you may have guessed, the firemen who is stationed here during a fire fighting and rescue operation would have a "helicopter view" of the whole building area.

Picture 08 - Closer view of the Firemen Intercom Master Panel


I zoomed in into the "mimic" of the master panel and added a few labels to give beginners a deeper understanding of Firemen Intercom Master Panel.

Observe the labels "CALL indicator" and "FAULT indicator".

Below the CALL on the mimic is a column of red-coloured lights (small very low-powered LED lamps). One for each location. I have labelled a few of the location to help

you understand better.

Beside each red LED is another similar LED of somewhat dark yellow color.

Now, if during a fire, a firemen who climbed up the fire escape staircase No 3 reaches the landing of the staircase at 19th Floor. If he picks up the firemen intercom

at that staircase, then the red LED on the console would light up.

This way he can communicate with his operation chief in the Main Fire Control Room. You can see an example of a fire intercom console  in Picture xx below.

During real fire fighting, fire fighters often cannot see anything beyond a few feet. He may not know precisely where he is. So if he picks up a firemen intercome,

then the chief in the control room can tell him precisely where he is.

Now the dark orange light next to the red one.

If the telecommunication cable is broken for some reason, for example due to some recent renovation work, then the dark yellow LED would light up.

Since the Fire Control Room is always attended by security personnel, someone would immediately know that this particular console is faulty and cannot be used.

Immediate action can then be taken to bring it back into normal service.

All systems and equipment for fire detection and fire fighting are there to protect human lives and properties.

Because of that, especially on he human lives part, their integrity and proper functioning at all times should never be compromised.

Picture 09 - The amplifier rack of a PA and Emergency Announcement System


I took this picture behind the amplifier rack of the PA and Emergency Announcement System in the Fire Control Room of a building project.

I apologize for the poor quality of the picture but this is the only one that I got.

I do not exactly go around taking pictures for this blog. I do what I do, and when I want to send a post for this blog I just search from whatever pictures in my hards

drive.

Sometimes I get lucky and the readers get to see nice pictures. At other times, my shots are just so bad it makes me wonder why I didn't check the quality of the

pictures immediately after I took them.

Picture 10 - The cabling behind the PA amplifier rack


This one is a bit better. It is from the same panel. I took the shot just to keep a record of the quality of the work in progress in case I need them later.

Picture 11 - Horn speaker at a basement carpark
(Click on the photo to enlarge it)

A high quality sound amplifier costing hundreds of thousand of dollars is of no use without the speaker to bring the sound to the public.

The above picture shows a horn speaker at a basement carpark. It is actually in the same project as the amplifier picture above.

Picture 12 - A close up view showing the wiring conduit also

Picture 13 - A close up view showing the mounting bracket and the wiring cable into from the conduit into the speaker unit

Picture 14 - Wall mounted box speaker above a staircase landing

Picture 15 - Security CCTV Master Panel in Fire Control Room

This one control panel has nothing to do with fire protection at all.

However, in real life design and construction of a building complex, it is an equipment that need to be closely coordinated with fire control and fire fighting

equipment inside the building control room.

Just look at the sheer size of the CCTV master panel. If not properly planned for during the design of the building layout, it can cause a real conngestion in the fire

control room.

Beginners should take note here. Even though architect can choose where she wants the fire control room to be, eventually the location is dictated by Fire Authority.

Once the design drawings are submitted to the Fire Department for approval, the fire officers can start exerting their power.

The best place for a fire control room is around the main entrance of the building, at the ground level.

During fire emergency, it is not good to have the fire fighters running around looking for fire control room. Every second lost can mean one more life lost in a real

bad fire situation.

Main entrance at ground floor is the best place for the main control room.

Guess what?? That is also an are with the highest price tags in a commercial building.

No building owner in their right mind would surrender such valuable commodity in big quantity.

In fact, after the design drawings have been approved by the fire authority, an owner may even squeeze down the size of the fire control room, citing all sorts of

commercial reasons.

That is why the control room should be properly sized for during design.

During construction, the supervising engineers should be vigilant to ensure that all equipment are manufactured to dimensions not exceeding the planned dimension.

Failure to exercise care here can affect someone's job security in that project.

Picture 16 - Another view of the CCTV master panel

I show this picture because I know there is always someone out there that need some ideas how to plan for this panel, especially young engineers in a design office.

So now you have some ideas of what to do, right?

Picture 17 - Example of a separate building for electrical substation

(Click on the picture to enlarge it)

I have explained at the beginning of this post about how good it is to design an electrical substation as a separate building near the main buidling complex.

Actually that applies to all mechanical and electrical plants that serve the building.

The above picture show one example that I can I can immediately show you.

I will not elaborate on this picture today. Readers can just study the picture and try to identify the plants.

I will send a short post just to explain on this picture some time in the near future.

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