Five implications on the design of internal doors when applying Technical Guidance Document M to the design of new works
There are a number of important differences between the guidance provided in Technical Guidance Document M 2000 and the new Technical Guidance Document M 2010 (TGD M 2010) which came into effect on the 1st January 2012. These differences should be considered at design stage and five of the implications of the differences in the design of internal doors are highlighted as below:
- Opening forces of internal doors: It is now a requirement that the opening forces of manually operable internal doors are suitable for independent use by all users (note that this applies to all accessible manual doors throughout a building). Section 1.3.3.2 (a) of TGD M 2010 states that the opening force when measured from the leading edge of the door, should be not more than 30N from 0° (the door in the closed position) to 30° open, and not more than 22.5N from 30° to 60°degrees of the opening cycle. Door opening forces can be measured by using a plunger-type force measuring instrument.
- Effective clear width of internal doors: Previously it was a requirement of Section 1.9 (a) of TGD M 2000 that internal doors provide a minimum clear opening width of not less than 750mm. This requirement has changed and Section 1.3.3.2 (b) of TGD M 2010 now states that the effective clear width through a single leaf door or one leaf of a double leaf door should be in accordance with Table 2 and Diagram 10. Table 2 of TGD M 2010 highlights the minimum clear widths of internal doors located in particular areas. For example a door located at right angles to an access route which is at least 1200mm wide must have a clear opening width of 825mm. It is important to note that door ironmongery such as lever/pull handles must not encroach on the effective clear width of a door.
- Vision panels: Previously it was a requirement of Section 1.9 (c) of TGD M 2000 that each leaf of a door in a corridor or passageway incorporates, where feasible and practicable, a glazed vision panel extending from 900 mm to 1500mm above the finished floor level. This requirement has changed and Section 1.3.3.2 (h) of TGD M 2010 now states that “where possible, unless for reasons of security or privacy, door leaves and side panels wider than 450mm should have vision panels towards the leading edge of the door whose vertical dimensions include at least he minimum zone or zones of visibility between 500mm and 1500mm from the floor. If a door has multiple viewing panels, the minimum zone of visibility should not be interrupted by opaque areas that obstruct more than 350mm of the vertical height of the zone. Diagram 10 of TGD M 2010 also provides a clear description of this requirement.
- Door handles: Section 1.9 (e) of TGD M 2000 previously stated that door ironmongery should be suitable for operation by people with disabilities however section 1.3.3.2(d) of TGD M 2010 goes beyond this explanation and describes the heights at which door handles and pull handles on doors should be located. Note that BS8300:2009 also provides additional design information on door handles.
- Door finishes/visual contrast: Section 1.3.3.2 (e), (f), (g) of TGD M 2010 now requires that doors, door frames and architraves must contrast visually with the surrounding walls and that all door opening furniture should contrast visually with the surface of the door. Another important point is that the leading edges of any doors which are not self closing or that will be kept open should also contrast visually with the other door surfaces. The specification of colours in these instances will be an important consideration.
If you would like further information on design implications of Part M 2010, please do not hesitate to contact one of our team on 01-4151285 or e-mail [email protected].
