AMD2 - Clause 422.2 - Cables in protected escape routes.

One could read this reg to require things that are only being possible in new buildings where dedicated cable runs can be cut, or the protected corridor gets smaller by a small partition to hide the wiring behind. 

The DPC said

422.2 Protected escape routes
Cables or other electrical equipment shall not be installed in a protected escape route unless they are part of an
essential fire safety or related safety system.
NOTE 1: Generally, this means cables in a protected escape route should be limited to lighting, emergency lighting and fire
detection and alarm systems, although cables for other safety systems may be necessary. Hospitals may have special
requirements as detailed in Section 710.
NOTE 2: Guidance is provided in Appendix 13.
422.2.1
(i)
Only cables that meet the following requirements shall be installed in protected escape routes:
resistance to flame propagation according to the recommended requirements of the relevant part of BS
EN 60332-3 (series) or, where cable management systems according to (i) or (ii) below are used, to the
recommended requirements of BS EN 60332-1-2 and

(ii)
a minimum of 60 % light transmittance when tested in accordance with BS EN 61034-2.

but the appendix 13 had the cop out "Cables installed in a fire resisting enclosure are deemed to be outside the protected escape route."

Steel trunking anyone ?

and  is the requirement for translucent conduit still there in the final version?

Mike.

PWW325

That is the definition of a Protected Escape Route. Yes you can run cables down this route on Unistrut and tray. After installation 2 layers of 12.5mm fire resistant plasterboard with staggered joints and a skim coat of plaster gives 2 hour fire protection. That is the way it is already done.

A protected escape route is already protected from attack by fire from within the building so using such routes as wire ways normally only requires 30min FR from within the protected escape route itself. So, for example, the normal practice of placing cables above suspended ceilings along corridors that are protected escape routes will need to ensure that the ceiling offers the appropriate FR. 
Your Approved Document B or our Part E guidance for the Building Regulations offers appropriate definitions for protected corridor, shaft and stair, all of which constitute the standard means of providing a protected escape route in the event of fire in a building.

The clause refers to the definition within the regs: "Protected escape route. A route enclosed with specified fire-resisting construction designated for escape to a place of safety in the event of an emergency"

I'm trying to highlight that currently the soffit above a demountable ceiling (if there is a ceiling at all) is quite often the fire line, not the ceiling itself. This new clause now precludes the installation of distribution cabling within such spaces.

I was wondering this. The most recent refurb Job I did we ran all elect services thru corridoors, to each apartment /flat.  However my take on the regs is that most protected routes will have a fire rated ceiling, and that the Ladder/tray is above the protected route as its bounded by the ceiling which is fire rated.  This doesnt get round the fact you need to provide a proper containment using ladder/tray etc.  But allows for other Electrical service sub-mains etc to pass thru the ceiling void above the protected route, which is not in it. IMO.  The revised regs dont change this ?

I think this is one of the biggest changes that has far reaching consequences.  In my field - railways, this is a huge change.

Protected escape routes can only be defined by the Responsible Person (RP) for the fire safety of the building, not the electrician or designer.  So the RP will need to be consulted so as to ascertain where the protected escape routes are.  Without that information, the designer will have to detail the lack of this information in their designers risk assessment and move on. 

The FRA should be revised annually so we can only hope that this is done properly when going into existing buildings.  If not within the FRA we should ask the question and have a paper trail back up that we tried if we do not get a response back.