Protected Routes and Travel Distances

[Firewolf]

Calling all fire safety officers, consultants and fire safety proffesionals!

Your help please...

If necessary where can travel distances  be discounted in a building? Is it at a protected staircase (ie one line of FR, storey exit) or a protected route (double door protection, corridor approach or lobbied approach)?

It may seem like an extremely silly question to ask but you would be amazed at how many people disagree on this issue!

So is it a protected staircase or a protected route - your interpretations please!

[PhilB]

Using blue guide/lilac guide travel distance is measured to nearest staircase that can be considered to be aprotected route.

Nothing to do with double door protection. Lobby or corridor approach and hopefully a final exit.

[Firewolf]

Hi Phil

Thanks for the reply. Playing devils advocate...

Please define how lobby protection and corridor approach aren't  "double door" protection.

The Blue guide does not mention that a protected route has to have lobby or corridor approach.It mentions that a protected route should have "appropriate FR"

[PhilB]

By two door I mean two fire doors, two fire doors are not required for a staircase to be considered a protected route. Non fire resisting corridor and one fire door enclosing stair = a staircase that can be considered a protected route and TD can be discounted.

Blue guide is quite clear, read page 74 14.48(b) a stairway can be considered a protected route if corridor or lobby approach.

Then read 14.46 when a stairway can be considered a protected route you can discount TD.

You cannot discount travel distance in protected corridors or stairs enclosed with a single line of FR.

[Firewolf]

Hi Phil

I promise Im not trying to be awkward! But just clear up the discussion

If a protected route can not be protected by just one line of FR how does your interpretation of one standard corridor door  + 1 x 30 mins FR door stand true?

[PhilB]

A protected route can be protected by one line of FR. a fire resisting corridor i.e single line of FR is a protected route.

However guidance document says you can only discount TD in STAIRCASES that can be considered to be protected routes. For a staircase to be considered a protected route lobby or corridor approach is required.

[Firewolf]

Thanks for your feedback it is greatly appreciated.

My colleagues here agree that the Blue Guide is very unclear in places and seems to contradict itself.

One last definition or anomolie to clear up is this. All protected routes in an office block MUST be lobbied if above 24 metres high.

We were wondering why you couldnt have corridor approach in this instance

Lets imagine that all floors in this office block has got corridors leading to staircases. The guide seems to suggest you need to form a lobby from the corridor into the staircase because of the 24 metre heigh rule. Is this the case in your opinion?

[PhilB]

I believe the theory is that you can rely more on lobby being maintained. Where as protected corridor approach may be compromised by any door along the corridor being wedged open.

Tall buildings may contain occupants for a long time so they have to be extra safe..hence lobby approach even when corridors are provided.

[Firewolf]

We totally agree with you on that.

If you couldnt form a lobby in these circumstances (trying to think of an example where this would happen) would making up the corridor be a suitable alternative - in other words true double door protection?

Thats our last question promise! :-)

[PhilB]

Approved document B would allow protected corridor or protected lobby, Scottish Tec Standards requires lobbies...risk appropriately.....protected corridors do the job if building is well managed.

So the answer is yes, no, maybe!!

[Slim Jim]

The Blue Guide may appear unclear in places, but the bottom line with protected route stairways is the restriction on the type of openings allowed into the stair.  It states that the only doors allowed to open into them are from toilets (low risk), lifts, corridors or lobbies, and exceptionally, low risk rooms.  Note that (other than low risk) rooms are not permitted.  This means that spaces containing combustible materials and ignition sources are less likely to affect the integrity of the stair enclosure in a fire situation, which is why we can disregard travel distances within the stair (a place of comparative safety).  As far as height goes, the higher the building, the longer period of time will be spent in the stair, thus requiring the additional protection of lobbies or protected corridors, as PhilB has stated.  Whatever the level of fire protection, travel distance tends to be included in all horizontal components of escape routes, but not in the vertical if suitably protected.

Don't forget that the Blue Guide was written by a deranged civil servant...will the new guides for the RRO echo the current guidance, and provide for a similar or even higher degree of protection than existing benchmarks?  Answers on a postage stamp please.

[Big A]

It would be nice to see one, wouldn't it?
=D

[colin todd]

If you have open plan, and no double door protection to the staircase, you still stop measuring travel distance at the door to the protected staircase.

[PhilB]

What? Who are we protecting Collllin, those in the open plan office or the other people using the stairs...basics Colllin....may I recommend a good foundation training course?

ADB and Blue guide differ for good reasons...if you're talking Blue Guide you can only stop TD in staircases that are protected routes...not those enclosed with single line FR.

[colin todd]

Whic word did you not understand,