number of exit doors in labs and prep rooms

Number of exit doors in labs and prep rooms: How many exit doors must a lab and a prep room have? Should they be on opposite sides of the lab? Are sliding doors allowed? Should the doors open outwards? How close to the fume cupboard can the exit door be?

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Publication Date: 06 March 2015
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number of exit doors in labs and prep rooms

Thank you for raising these very important questions with Science ASSIST.  They are among the issues that will be addressed more fully in the current Science ASSIST project regarding the design requirements for school science teaching areas.

The question of access and egress in school science laboratories deserves careful consideration and risk assessment.  Science areas use higher-risk materials and equipment than normal classrooms. In an emergency situation, the logistics of the rapid egress of in excess of 30 people in an emergency need to be considered. Where there are a number of students working in a hazardous environment, a local risk assessment should inform best practice, and this is most easily incorporated at the planning stage prior to construction.

Summary Response:

In summary, the answers to your questions are as follows.  Further supporting details follow this summary. Science ASSIST strongly recommends that the following provisions are followed to facilitate emergency exit in the event of an emergency such as a fire or chemical spill.

  • A school science laboratory should have at least two exit doors, and they should be widely separated so as to facilitate emergency exit should one of these be obstructed.
  • The number of exits required for a science preparation room would depend on both the size of the room and a local risk assessment.  If the point of egress from any part of the room is greater than 7 metres, a second exit door is required. We recommend that preparation rooms have at least two exits. 
  • A chemical storeroom, usually being a much smaller room, would normally require only one exit.  For reasons of security of the stored chemicals, we would recommend that chemical store rooms should have just one door that opens outwards, is capable of being secured in the open position, is lockable from the outside, but able to be opened from the inside without the use of a key.
  • Exit doors should open in the direction of egress.  Sliding doors are therefore not appropriate for this use.
  • Any door, including an exit door, must not be situated closer than 1.5 metres from the front (sash) of a fume cupboard, or closer than 1 metre from the side wall of a fume cupboard.

Egress requirements of the Building Code

Requirements for access and egress are given in the Building Code of Australia 2015, Volume 1.  In the Code (BCA) school class rooms including school science laboratories are classified as Class 9b.  The following information is from the BCA.

Number of exits required

At least two exits are required for any school building storey (including science areas) where there are 2 or more storeys, and for any storey (including a single ground level building) which accommodates more than 50 persons.  (See Volume 1, Part D1 Provision for Escape, D1.2 Number of exits required, p 159.)

Swinging doors

Swinging exit doors must open in the direction of egress, and must not impede egress through the exit or in the passage into which they open. (See Volume 1, Part D2 Construction of Exits, D2.20 Swinging Doors, p185.)  The provision for the open door to not impede traffic in the passage way is usually achieved by recessing the hinges of the door(s) partly into the room.

Operation of latch

An exit door must be able to be readily opened from the inside without the use of a key. (See Volume 1, Part D2 Construction of Exits, D2.21 Operation of Latch, p186.)  These latches are commonly the “safety bar” type operated with a single downwards push.

 

Egress requirements of the AS/ NZS 2982:2010

The AS/NZS 2952:2010 Laboratory design and construction specifies:

2.11 EGRESS AND ACCESS

An unobstructed egress path shall be provided from each laboratory.

Compliance with the egress limits of the Building code shall be regarded as a minimum requirement. Laboratories with high hazards requiring rapid egress (e.g. a fast developing fire) should have a shorter egress travel limits determined by an appropriate risk assessment.

Corridor and door widths shall be large enough to allow routine transfer of laboratory equipment.

NOTE: Wide or double doors are often required for the movement of large items.[i]

A risk assessment of a school science laboratory might conclude that because of the perceived higher risk of the area, and the possible large number of students and staff who would need to exit in the event of an emergency, that at least two exits are provided. 

 

It is the strong advice of Science ASSIST that school science laboratories should be equipped with at least two compliant exits.

 

Further supporting information

We draw your attention to the following information taken from LABCON 2003 Lab Design session. 

1.3.3 Access and Egress – The ‘Ins’ and ‘Outs’

Previous editions of AS2243.1: 1997 included detailed descriptions of the number, siting, spacing and opening of doorways in laboratories. The Standard was amended in 1999, and the Building Code of Australia (BCA) now describes the minimum conditions required for access and egress.

Under the BCA Section D2.20 and D2.21 the following provisions are mandatory for doorways that are deemed required exits or form part of a required exit, or in the path of travel to a required exit. (A required exit is one that has been so deemed to satisfy the access and egress requirements of the BCA.)

  • Swinging doors in rooms less than 200 m2 that are the only exit from the room must be fitted with a device to hold the door open. Otherwise they must swing in the direction of egress.
  • Doorways must be unobstructed and the doors must not impede the path or direction of egress to or through a required exit.
  • The latch on an exit door should be a level or ‘panic bar’ type. The door lock must be openable from the inside without a key. The door should not be lockable against egress.

The following details are taken from the pre-1997 AS2243.1. They are not mandatory. However, they are still considered best practice to ensure that, in the event of fire, chemical spill or other emergency, escape from the area is swift, direct, and not impeded by classroom activities, or effect of the fire or emergency.

  • Laboratories and classrooms should have at least two separate means of egress; at least one opening directly to the outside or a corridor that has external egress. The other may open into another room with an exit to the outside or corridor that has an external egress.
  • Small laboratories sub-compartments, such as chemical storerooms, may have only one access door provided that the distance of travel to the door from any point in the room does not exceed 7 metres.
  • Where there are two or more doors, the distance between them should be at least 12.5 metres, or 20% of the perimeter of the room (whichever is the lesser) i.e. for a classroom 10 x 11 metres the distance between the two exits doors should be at least 8.5 metres.
  • The doors should have a glazed vision panel. In a fire door this panel must not compromise the fire rating.
  • The egress doors should open in the direction of egress, and should be recessed so that it does not impede traffic in the corridor.[ii]

While this source is somewhat dated and refers to an earlier version of the Standard, the information given is very clearly set out, and Science ASSIST regards it as excellent advice.  These requirements are also consistent with those given in the various state education department design briefs for schools that we have been able to access.  At this stage, Science ASSIST is not sure to what extent any provisions not covered in the current Building Code are mandated, and is seeking further clarification on this point.

Siting of Exit Doors and Fume Cupboards:

The requirements for a fume cupboard to be at least 1.5 metres (sash) and 1 metre (side wall) from a door including an exit door are specified in AS/NZS 2243.8.2014.  These requirements are set to facilitate the efficient operation of the fume cupboard and to avoid undue interference of air flow caused by proximity to a doorway.  These requirements are shown in the following illustration taken from AS/NZS 2243.8.2014 Safety in Laboratories - Fume Cupboards[iii]

FIGURE 1 MINIMUM SPACINGS THAT AVOID UNDUE DISTURBANCE OF AIRFLOW

References:

 

[i] This extract is from AS/NZS 2982.2010 Laboratory Design and Construction reproduced with permission from SAI Global Ltd under Licence 1407-c117

[ii] Benedetti, Simon, Clark, Margot, Eckardt, Glenn, Edwards, Jill. 2002. LTAV LABCON 2003 Lab Design Session. Reviewed and revised by Margot Clark for presentation at VIEU School Officers’ Conference, August 27th 2003. This extract is reproduced with permission from LTAV.

[iii] This extract is from AS/NZS 2243.2014 Safety in laboratories Part 8: ‘Fume cupboards” reproduced with permission from SAI Global Ltd under Licence 1407-c117

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