Sprinklers in unheated "non-habitable" area?

[Guest Tommy Johnson]

Hello,  our apartment in a converted mill (discussed in fire door forum) has a lift accessing our apartment directly.

The entrance lobby to our apartment consists of a front door to the communal stairwell, a door between the lift doors and our entrance lobby area, then double doors to the main living areas.  These are all fire doors.

Our entrance lobby is above an unheated communal area of the block (entrance/mail area/lift lobby), our lobby area we are told is none habitable, and thus has no heating or plug sockets in this large lobby  are (approx 18 square meters).  Our lobby area does have sprinklers installed, I believe it is a wet system.  

My concern is that due to this area being unheated, it gets very cold in there, when the lift is in operation it displaces cold air (pretty much external temperature) beneath and around the the fire door separating the lift door to our lobby.  

When we are away from the apartment we set the temp to 10c to prevent pipes freezing, however as the lobby area is unheated, we are worried about the sprinkler system becoming damaged during cold snaps.

The question I have is, should this area be heated if there is a sprinkler system in it to prevent damage, especially considering it is an unheated area?

Can we leave the double doors to the main living areas open (magnetic releases installed) to try and get some warmth in there? (doesn't really help)

Thank you!

 

 

[AnthonyB]

Assuming it's a residential system to BS9521 if correctly designed and installed the following should have been accounted for:

5.12 Frost protection

Freezing can lead to burst pipes, inhibiting the movement of water through the sprinkler system and preventing discharge from the sprinklers.

Normal methods of protection against freezing include:
• installing pipework within the heated envelope of the dwelling;
• the use of lagging and trace heating;
• antifreeze.

Unlike water in domestic water systems, water in sprinkler systems is not replenished by warmer water in normal circumstances. Therefore the water in a sprinkler system
continues to lose heat until it reaches ambient air temperature and can therefore easily freeze, despite being lagged. Exposed pipework, unless adequately protected,
can also be affected by wind-chill leading to the freezing of the contents, even when ambient temperatures are above 0 °C.
Any water-filled pipework, pump(s) or container(s) used in the sprinkler system, which might be subjected to temperatures below 4 °C, should be protected
against freezing.
If antifreeze is used, it should meet the following recommendations.
a) Antifreeze is flammable. It should therefore be sufficiently diluted and thoroughly mixed. Only approved premixed solutions that can be evidenced as suitable for sprinkler systems should be used.
b) The use of antifreeze solutions in water systems connected to wholesome water supplies should have appropriate backflow protection.
c) Only glycerine-based anti-freeze solutions may be used with plastic pipe and fittings. Glycol-based anti-freeze solutions should not be used in CPVC systems as it can damage the plastic.
d) The use of antifreeze solutions in water systems connected to wholesome supplies requires a level of backflow protection which is greater than for systems without antifreeze. The water provider (e.g. water undertaker) should be consulted regarding the fluid categorization and the suitability of backflow prevention arrangements prior to installation. 

[Guest Tommy Johnson]

On 12/12/2022 at 20:01, AnthonyB said:

Assuming it's a residential system to BS9521 if correctly designed and installed the following should have been accounted for:

5.12 Frost protection

Freezing can lead to burst pipes, inhibiting the movement of water through the sprinkler system and preventing discharge from the sprinklers.

Normal methods of protection against freezing include:
• installing pipework within the heated envelope of the dwelling;
• the use of lagging and trace heating;
• antifreeze.

Unlike water in domestic water systems, water in sprinkler systems is not replenished by warmer water in normal circumstances. Therefore the water in a sprinkler system
continues to lose heat until it reaches ambient air temperature and can therefore easily freeze, despite being lagged. Exposed pipework, unless adequately protected,
can also be affected by wind-chill leading to the freezing of the contents, even when ambient temperatures are above 0 °C.
Any water-filled pipework, pump(s) or container(s) used in the sprinkler system, which might be subjected to temperatures below 4 °C, should be protected
against freezing.
If antifreeze is used, it should meet the following recommendations.
a) Antifreeze is flammable. It should therefore be sufficiently diluted and thoroughly mixed. Only approved premixed solutions that can be evidenced as suitable for sprinkler systems should be used.
b) The use of antifreeze solutions in water systems connected to wholesome water supplies should have appropriate backflow protection.
c) Only glycerine-based anti-freeze solutions may be used with plastic pipe and fittings. Glycol-based anti-freeze solutions should not be used in CPVC systems as it can damage the plastic.
d) The use of antifreeze solutions in water systems connected to wholesome supplies requires a level of backflow protection which is greater than for systems without antifreeze. The water provider (e.g. water undertaker) should be consulted regarding the fluid categorization and the suitability of backflow prevention arrangements prior to installation. 

Hello and thank you for your response.  Very helpful to a complete novice.

I've received a copy of the final fire plan from the developer and it states the following.

"4.2 Automatic fire suppression

Each apartment will be provided with an automatic sprinkler system conforming to BS 9251:2014 and designed as a Category 2 system. "

So with this is in mind, I guess I should challenge them on what frost protection has been installed to prevent the risk of damage to the system in the unheated area.

I am sure they will continue to state there are no issues, but will be interesting to see their response.