Network cabinet - fire mitigation

[Tim Watts]

I'm looking to site a small 19" network cabinet in my attic space, near
the main ELV cable tray.

It will contain some running equipment - PoE network switch, IP Cam
recorder, UniFi Wifi controller.

Probably not my 2 small servers - they;d be better on a shelf in the
hall. So probably 200-300 watts of net consumption at worst - ie needs
some ventilation but not loads.

Mindful of a piece of faulty equipment not starting a fire in a space
filled with wood and stored "stuff", I am thinking of a full metal
cabinet, the sort with lots of small vent holes/slots all over.


My feeling is:

*If* (and it's rare, but I have seen it happen, couple of items from
1000s of bits of kit I've been involved with over the decades) a bit of
equipment incinerates, that doing so inside a metal box is likely to
significantly reduce the likelihood of any fire spreading outside before
fuses blow and the source of the fire quenches. There after all is not
actually that much burnable material in say a metal boxed network switch.

Given a bundle of Cat-x cables are coming in, let's also assume I'll use
low-smoke LSZH type cables as far as practical.


Any comments?

[Bob Minchin]

What is the construction of your roof? If it is a modern warm roof then
you might be OK but if it is a traditional cold roof, it will get
stupidly hot in summer and almost certainly kill your equipment.

Post by Tim Watts
I'm looking to site a small 19" network cabinet in my attic space, near
the main ELV cable tray.
It will contain some running equipment - PoE network switch, IP Cam
recorder, UniFi Wifi controller.
Probably not my 2 small servers - they;d be better on a shelf in the
hall. So probably 200-300 watts of net consumption at worst - ie needs
some ventilation but not loads.
Mindful of a piece of faulty equipment not starting a fire in a space
filled with wood and stored "stuff", I am thinking of a full metal
cabinet, the sort with lots of small vent holes/slots all over.
*If* (and it's rare, but I have seen it happen, couple of items from
1000s of bits of kit I've been involved with over the decades) a bit of
equipment incinerates, that doing so inside a metal box is likely to
significantly reduce the likelihood of any fire spreading outside before
fuses blow and the source of the fire quenches. There after all is not
actually that much burnable material in say a metal boxed network switch.
Given a bundle of Cat-x cables are coming in, let's also assume I'll use
low-smoke LSZH type cables as far as practical.
Any comments?

[Tim Watts]

Post by Bob Minchin
What is the construction of your roof? If it is a modern warm roof then
you might be OK but if it is a traditional cold roof, it will get
stupidly hot in summer and almost certainly kill your equipment.

Good question and it's a retro warm roof (from the POV of being inside).

That is to say, there is 75mm celotex between the rafters, 15mm under
and then 9.5mm PB over the more accessible parts to protect the celotext
from dents and fire.

The attic is thermally part of the upstairs room (thin pannelling will
separate them)

[Tim Watts]

Post by Tim Watts

Post by Bob Minchin
What is the construction of your roof? If it is a modern warm roof
then you might be OK but if it is a traditional cold roof, it will get
stupidly hot in summer and almost certainly kill your equipment.

Good question and it's a retro warm roof (from the POV of being inside).
That is to say, there is 75mm celotex between the rafters, 15mm under
and then 9.5mm PB over the more accessible parts to protect the celotext
from dents and fire.

^^^ 25mm under

Post by Tim Watts
The attic is thermally part of the upstairs room (thin pannelling will
separate them)

[Brian Gaff]

Yes some insulation needed and perhaps forced ventilation too. There used to
be a fire detecting extinguisher available for such racks back in the 80s,
but cannot remember where from now.
Brian
--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
***@blueyonder.co.uk
Blind user, so no pictures please!

Post by Bob Minchin
What is the construction of your roof? If it is a modern warm roof then
you might be OK but if it is a traditional cold roof, it will get stupidly
hot in summer and almost certainly kill your equipment.

Post by Tim Watts
I'm looking to site a small 19" network cabinet in my attic space, near
the main ELV cable tray.
It will contain some running equipment - PoE network switch, IP Cam
recorder, UniFi Wifi controller.
Probably not my 2 small servers - they;d be better on a shelf in the
hall. So probably 200-300 watts of net consumption at worst - ie needs
some ventilation but not loads.
Mindful of a piece of faulty equipment not starting a fire in a space
filled with wood and stored "stuff", I am thinking of a full metal
cabinet, the sort with lots of small vent holes/slots all over.
*If* (and it's rare, but I have seen it happen, couple of items from
1000s of bits of kit I've been involved with over the decades) a bit of
equipment incinerates, that doing so inside a metal box is likely to
significantly reduce the likelihood of any fire spreading outside before
fuses blow and the source of the fire quenches. There after all is not
actually that much burnable material in say a metal boxed network switch.
Given a bundle of Cat-x cables are coming in, let's also assume I'll use
low-smoke LSZH type cables as far as practical.
Any comments?

[John Rumm]

Post by Tim Watts
I'm looking to site a small 19" network cabinet in my attic space, near
the main ELV cable tray.
It will contain some running equipment - PoE network switch, IP Cam
recorder, UniFi Wifi controller.
Probably not my 2 small servers - they;d be better on a shelf in the
hall. So probably 200-300 watts of net consumption at worst - ie needs
some ventilation but not loads.
Mindful of a piece of faulty equipment not starting a fire in a space
filled with wood and stored "stuff", I am thinking of a full metal
cabinet, the sort with lots of small vent holes/slots all over.
*If* (and it's rare, but I have seen it happen, couple of items from
1000s of bits of kit I've been involved with over the decades) a bit of
equipment incinerates, that doing so inside a metal box is likely to
significantly reduce the likelihood of any fire spreading outside before
fuses blow and the source of the fire quenches. There after all is not
actually that much burnable material in say a metal boxed network switch.
Given a bundle of Cat-x cables are coming in, let's also assume I'll use
low-smoke LSZH type cables as far as practical.
Any comments?

That pretty much describes most comms cabinets these days... (although
they normally have a glass front door). e.g:

https://www.comms-express.com/products/datacel-6u-wall-mounted-data-cabinet-data-rack-390mm-deep/

You could clad it in insulation for added fire protection and protection
from ambient temperatures in the loft, but then you would need to have
some active airflow through the cabinet. You could fit a network
connected temperature sensor. (I note that some of the draytek wireless
APs have that built in now).

If you are fitting mains interlinked smoke detectors, then fitting one
in the loft would seem like a good idea.

The first cabinet I used domestically was a plastic cabinet (only
because they were available in smaller sizes and significantly cheaper
at the time). I more recently rehoused everything in a metal one as I
needed more space (and these days the metal ones are pretty cheap). Mine
is in an under stair cupboard, so perhaps more noticeable if things were
to get too toastie!
--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

[Tim Watts]

Post by John Rumm

Post by Tim Watts
I'm looking to site a small 19" network cabinet in my attic space, near
the main ELV cable tray.
It will contain some running equipment - PoE network switch, IP Cam
recorder, UniFi Wifi controller.
Probably not my 2 small servers - they;d be better on a shelf in the
hall. So probably 200-300 watts of net consumption at worst - ie needs
some ventilation but not loads.
Mindful of a piece of faulty equipment not starting a fire in a space
filled with wood and stored "stuff", I am thinking of a full metal
cabinet, the sort with lots of small vent holes/slots all over.
*If* (and it's rare, but I have seen it happen, couple of items from
1000s of bits of kit I've been involved with over the decades) a bit of
equipment incinerates, that doing so inside a metal box is likely to
significantly reduce the likelihood of any fire spreading outside before
fuses blow and the source of the fire quenches. There after all is not
actually that much burnable material in say a metal boxed network switch.
Given a bundle of Cat-x cables are coming in, let's also assume I'll use
low-smoke LSZH type cables as far as practical.
Any comments?

That pretty much describes most comms cabinets these days... (although
https://www.comms-express.com/products/datacel-6u-wall-mounted-data-cabinet-data-rack-390mm-deep/
You could clad it in insulation for added fire protection and protection
from ambient temperatures in the loft,

Forgot to say, but Bob asked, the attic is thermally part of the
upstairs - so warm (but not baked in summer) and dry and otherwise
fairly airtight from the outside.

but then you would need to have

Post by John Rumm
some active airflow through the cabinet. You could fit a network
connected temperature sensor. (I note that some of the draytek wireless
APs have that built in now).
If you are fitting mains interlinked smoke detectors, then fitting one
in the loft would seem like a good idea.

Yes - I do and adding one in the void may not be a bad idea.

Post by John Rumm
The first cabinet I used domestically was a plastic cabinet (only
because they were available in smaller sizes and significantly cheaper
at the time). I more recently rehoused everything in a metal one as I
needed more space (and these days the metal ones are pretty cheap). Mine
is in an under stair cupboard, so perhaps more noticeable if things were
to get too toastie!

[t***@gmail.com]

Post by Tim Watts

Post by John Rumm

Post by Tim Watts
I'm looking to site a small 19" network cabinet in my attic space, near
the main ELV cable tray.
It will contain some running equipment - PoE network switch, IP Cam
recorder, UniFi Wifi controller.
Probably not my 2 small servers - they;d be better on a shelf in the
hall. So probably 200-300 watts of net consumption at worst - ie needs
some ventilation but not loads.
Mindful of a piece of faulty equipment not starting a fire in a space
filled with wood and stored "stuff", I am thinking of a full metal
cabinet, the sort with lots of small vent holes/slots all over.
*If* (and it's rare, but I have seen it happen, couple of items from
1000s of bits of kit I've been involved with over the decades) a bit of
equipment incinerates, that doing so inside a metal box is likely to
significantly reduce the likelihood of any fire spreading outside before
fuses blow and the source of the fire quenches. There after all is not
actually that much burnable material in say a metal boxed network switch.
Given a bundle of Cat-x cables are coming in, let's also assume I'll use
low-smoke LSZH type cables as far as practical.
Any comments?

That pretty much describes most comms cabinets these days... (although
https://www.comms-express.com/products/datacel-6u-wall-mounted-data-cabinet-data-rack-390mm-deep/
You could clad it in insulation for added fire protection and protection
from ambient temperatures in the loft,

Forgot to say, but Bob asked, the attic is thermally part of the
upstairs - so warm (but not baked in summer) and dry and otherwise
fairly airtight from the outside.
but then you would need to have

Post by John Rumm
some active airflow through the cabinet. You could fit a network
connected temperature sensor. (I note that some of the draytek wireless
APs have that built in now).
If you are fitting mains interlinked smoke detectors, then fitting one
in the loft would seem like a good idea.

Yes - I do and adding one in the void may not be a bad idea.

Post by John Rumm
The first cabinet I used domestically was a plastic cabinet (only
because they were available in smaller sizes and significantly cheaper
at the time). I more recently rehoused everything in a metal one as I
needed more space (and these days the metal ones are pretty cheap). Mine
is in an under stair cupboard, so perhaps more noticeable if things were
to get too toastie!

Ye oldie bimetal room thermostat set to 30 in the cabinet could cut power in case of fire, you'd just need to ensure just enough airflow to avoid it hitting 30C in normal use.

I wouldn't insulate the cab, it won't help in case of fire, it'll make it worse, and it won't help with anything else.


NT

[Tim Watts]

Post by t***@gmail.com
Ye oldie bimetal room thermostat set to 30 in the cabinet could cut power in case of fire, you'd just need to ensure just enough airflow to avoid it hitting 30C in normal use.

A bit of old-skool protection wouldn't be a bad idea. Could even stick a
low temperature thermal fuse in a small box with some vent holes inside
the cabinet.

Post by t***@gmail.com
I wouldn't insulate the cab, it won't help in case of fire, it'll make it worse, and it won't help with anything else.

I agree (I think there was an assumption the attic was cold, it's not).

I'm thinking to maybe line a space with PB (the roof is already lined) a
few inches bigger all round than the cabinet then site the cabinet in
there. Stick a couple of intumescent air vents top and bottom for some
basic convection.

[t***@gmail.com]

Post by Tim Watts

Post by t***@gmail.com
Ye oldie bimetal room thermostat set to 30 in the cabinet could cut power in case of fire, you'd just need to ensure just enough airflow to avoid it hitting 30C in normal use.

A bit of old-skool protection wouldn't be a bad idea. Could even stick a
low temperature thermal fuse in a small box with some vent holes inside
the cabinet.

Post by t***@gmail.com
I wouldn't insulate the cab, it won't help in case of fire, it'll make it worse, and it won't help with anything else.

I agree (I think there was an assumption the attic was cold, it's not).
I'm thinking to maybe line a space with PB (the roof is already lined) a
few inches bigger all round than the cabinet then site the cabinet in
there. Stick a couple of intumescent air vents top and bottom for some
basic convection.

You could but I don't think it's needed. A fire inside the cab quickly goes out if there's little external airflow.


NT

[Huge]

On 2018-02-14, Tim Watts <***@dionic.net> wrote:

[26 lines snipped]

Post by Tim Watts
Any comments?

Any way of fitting some sort of extinguishing system? One of those
vehicle types where a fire melts a plastic tube which squirts extinguishant,
perhaps?

[s***@gowanhill.com]

Post by Tim Watts
I'm looking to site a small 19" network cabinet in my attic space, near
the main ELV cable tray.

Fire extinguishers are available eg

https://www.safelincs.co.uk/redetec-fm200-automatic-fire-suppression-unit/

or you can get small halon-replacement cylinders eg

https://www.safelincs.co.uk/fireblitz-automatic-fe36-fire-extinguisher/

You can get relay interface bases for most common smoke detectors, so if it detects smoke it could cut the power to the rack. This might be more reliable than a high-temp thermostat especially for a smouldering plasticy fire.

Owain

[Tim Watts]

Post by s***@gowanhill.com
https://www.safelincs.co.uk/fireblitz-automatic-fe36-fire-extinguisher/

That's really interesting - relatively inexpensive - thanks!

Post by s***@gowanhill.com
You can get relay interface bases for most common smoke detectors, so if it detects smoke it could cut the power to the rack. This might be more reliable than a high-temp thermostat especially for a smouldering plasticy fire.

Yes - I think I've seen those for the Ei-Aico units I have.

Great ideas...

[Dave Liquorice]

Post by s***@gowanhill.com
You can get relay interface bases for most common smoke detectors, so if
it detects smoke it could cut the power to the rack. This might be more > reliable than a high-temp thermostat especially for a smouldering
plasticy fire.

Interesting idea but is there a UPS? I guess you could put the break
after the UPS but it needs to be fail safe, ie no power = UPS
disconnected otherwise there are possibilties that power (from the
UPS) is supplied when you don't want it to be. But you have to
account for power cuts when you do want power from the UPS.

And if interlinked, which is also a good idea, you don't want the
rack power dumped when you burn the toast.

I'm sure it's possible but needs a bit of thought and careful
examination of the logic truth table of anything designed.