Fire rated glass alternative - could Acrylic/Polycarbonate sheet (class 1 or 3???) be used?

[jamphi24]

Hi
I had a loft conversion and to meet building regs I need to separate my stairs on the ground floor which is open plan.
To maintain the open plan feel I was looking to use FD30 fire rated glass to separate it which is obviously very expensive.
It got my thinking could I potentially use Acrylic sheet or Polycarbonate Sheet instead. I have read that these come in either class 1 or class 3 fire ratings but I don't really understand how this equates in FD30 terms?
Any thoughts or is fire rated glass the only option?

Thanks in advance for help.

 

[OwainDIYer]

Class 1 or 3 refers to the spread of flame along a surface which could allow a fire to travel along a passage.

It does not refer to retaining structural integrity in the event of a fire, which fire door ratings do.

Your Building Control might accept sprinklers as an alternative.

 

[Nakajo]

Building Control might accept mains and interlinked smoke alarms. They did on my house.

 

[^woody^]

Building Control might accept mains and interlinked smoke alarms. They did on my house.

They accepted 50mm cavities on my house, but then again I don't have an open plan ground floor.

 

[Awritebutt]

Building Control might accept mains and interlinked smoke alarms. They did on my house.

No idea why any building control body in the land would deem this acceptable (Assuming the floor you added is over 4.5m). I cant see any guidance in AD B vol1 or BS 9991 that would allow this. The whole requirement of B1 is Means of Warning and Escape, granted the warning is fine but the escape is not!

Curiosity has me here. Was this LABC or an AI?

 

[Awritebutt]

Hi
I had a loft conversion and to meet building regs I need to separate my stairs on the ground floor which is open plan.
To maintain the open plan feel I was looking to use FD30 fire rated glass to separate it which is obviously very expensive.
It got my thinking could I potentially use Acrylic sheet or Polycarbonate Sheet instead. I have read that these come in either class 1 or class 3 fire ratings but I don't really understand how this equates in FD30 terms?
Any thoughts or is fire rated glass the only option?

Thanks in advance for help.

Technically you only need an FD20 door. Appendix B in Approved Document B Vol1 goes into detail on fire doors and the requirement and what you can and cannot use, the area you are currently describing is for surface spread of flame and not fire integrity. One other option i have seen in the past, assuming cost would be greater for this, is having smoke curtains installed on the ground floor that activate on fire alarm. People like this as it allows for the open plan nature to stay but will stop the smoke spreading through a protected stair.

 

[cjard]

The whole requirement of B1 is Means of Warning and Escape, granted the warning is fine but the escape is not!

The approved documents are merely Secretary of State approved guidance as to how one may construct in accordance with the law. It is not mandatory that they be slavishly adhered to. Nakajo's BI may have taken the same pragmatic approach that mine did; it is smoke inhalation that kills most occupants within a few minutes, not structural collapse killing them within a few tens of minutes or blocking off their exit route. Fire doors no longer require closers, meaning they can now be left open, nullifying their entire raisin d'etre. Much better that we employ dedicated systems to manage and minimise fire risk rather than hope occupants exhibit a particular pattern of behaviour. From your smoke curtains comment i figure you also appreciate this

 

[Nakajo]

Besides, raisins can and should be put to better use.

 

[Awritebutt]

The approved documents are merely Secretary of State approved guidance as to how one may construct in accordance with the law. It is not mandatory that they be slavishly adhered to. Nakajo's BI may have taken the same pragmatic approach that mine did; it is smoke inhalation that kills most occupants within a few minutes, not structural collapse killing them within a few tens of minutes or blocking off their exit route. Fire doors no longer require closers, meaning they can now be left open, nullifying their entire raisin d'etre. Much better that we employ dedicated systems to manage and minimise fire risk rather than hope occupants exhibit a particular pattern of behaviour. From your smoke curtains comment i figure you also appreciate this

You are correct in saying that the guidance in Approved Document B is not the law. However if you look at the requirements of B1:

Means of warning and escape
B1. The building shall be designed and constructed so that there are appropriate provisions for the early warning of fire, and appropriate means of escape in case of fire from the building to a place of safety outside the building capable of being safely and effectively used at all material times.

In what way is having a mains and interlinked smoke alarms with no protection to the stair an appropriate means of escape? The only box that ticks is for the early warning of fire. Too many people say guidance is just guidance but there has to be approach to show how compliance is achieved for appropriate means of escape. In my opinion this is not acceptable approach as it does not stop the spread of smoke or fire. No guidance out there says this is an acceptable approach.

 

[^woody^]

In what way is having a mains and interlinked smoke alarms with no protection to the stair an appropriate means of escape?

Because early warning allows early escape via an unprotected route.

Its all about risk assessing the property and actual risk nowadays.

 

[^woody^]

Besides, raisins can and should be put to better use.

Mention the fruit of Satan again and you are blocked.

 

[Awritebutt]

Because early warning allows early escape via an unprotected route.

Its all about risk assessing the property and actual risk nowadays.

As stated in the requirement an appropriate means of escape in case of fire from the building to a place of safety outside the building, no risk assessing would take this away as its a sleeping risk. No Building control officer should be accepting this without a valid design and the only person i could see justifying this would be a fire engineer. If you look up any LABC guidance they provide to homeowners/builders/designers it will tell you the same thing.

There is only one way i can see this solution work is if the building is of historical or architectural merit then it may be considered if its achievable but even nowadays its even hard to get that past a building inspector.