Internal door clear widths on first floor

Charlie-Bravo

Just checking through some information and may have caught a snag which needs dealing with.

The scenario is a typical semi-d with normal accessible Part M arrangement on ground floor. At first floor level, doors installed are 30" (760mm) wide leafs. The effective clear width is 705mm when opened. What is the minimum clear width on this? I would have understood that Part B applies (I know it's a dwelling with low occupancy) and minimum 'escape' clear width of 750mm applies?

Gumbo

When was the house built?

Charlie-Bravo

Let's just say it's brand new!

Gumbo

astrofluff wrote: »

Let's just say it's brand new!

Brand new then it should comply with TGDM 2010 so the 750mm figure should be in play as you know.

Seems a silly mistake on the developer.
I'd have to open Part M to confirm but there are allowances for the first floor of a single family dwelling given that anybody confined to a wheelchair will be at ground floor level only.

Charlie-Bravo

Cheers, I've opened Part M 2010. There is a paragraph on pg 115, right hand column, 3rd paragraph down:

Doors to rooms (other than cloak rooms,
hot presses, etc), which can only be
accessed by the use of steps or stairs,
may have a minimum effective clear width
of 750 mm.

My question would be, when reading down through Section 3.3 (circulation within a dwelling), does this paragraph relate to dwellings with no habitable room on the entrance storey? And any habitable room in a storey accessed by steps need only be ambulant disabled compliant hence the 750mm clear width requirement?!

Just seeking reassurance and maybe both Part B and Part M stating 750mm clear is enough! Something to mull over....

mickdw

It was a typical spec for years gone by to go with 2' 6'' doors on first floor.
No place for it nowadays.

PMBC

It was always 'beyond me' why door widths of 29.5/30" were allowed instead of giving a comfortable width. Wouldn't it save on blockwork!!
To be serious I think that historically 'door opening' and 'door (leaf) width' were used interchangeably.

Charlie-Bravo

That's why 'clear width' wording is used. But what's funny is that in the measurement for clear width in Part B it allows ironmongery to project into the clear width while Part M is clear width between jamb and ironmongery.

PMBC

Doesn't make sense, that; so TGD M trumps B. Interesting. Thanks.

Metric Tensor

I don't think one "trumps" the other as such.

You just have to comply with both and one is more onerous than the other. You're still compliant with B if you meet M.

Living in an older house here and it's all 2' 6" doors. Not a one of them meets 750 though!

PMBC

That was the intended meaning - the more onerous must be satisfied.:D:)

Charlie-Bravo

I suppose the mentality is that a wheelchair user will need a full clear width straight through whereas under Part B most people can bend around the projection on an escape route - but yes M trumps B. Another thought on clear widths, take for example the clear width of windows, it being 450mm minimum, it allows for the escapee to maneuver at an angle out the window! You would pivot out a window when getting out.

PMBC

You comments are very interesting as I had thoughts also about windows and their openings. I recall under the original/1992? TGDs the notion of 'clear opening'. We had a notional figure of an opening window that would satisfy that requirement. In those days friction hinges were very popular - ?still are? - but resulted in the window part that opened (I'm reluctant to use words like sash and casement as they are no longer pertinent or properly descriptive) moving in to the 'clear width' thus reducing the effective width. A top hung opening on an attic window is even more restrictive. However your idea of exiting at an angle or of pivoting is practical and correct.
Thanks for your observation.