As a multidisciplinary Architectural & Engineering team, we get asked a lot of questions relating to the application of the National Construction Code (NCC) through the design phase of (pharmaceutical) facilities in Australia. A common question relates to the provision for escape.
Pharmaceutical manufacturing facilities are generally considered to have a high fire hazard potential due to the nature of operations performed. It is not unusual for emergencies to occur within or in close proximity to a facility. Therefore, through the design phase, we are expected to consider the safety of occupants in case of emergency.
Facility design should allow people to easily navigate their route out of the building and reach a safe place as quickly as possible if necessary.
In this regard, the provision for escape is of critical importance and the NCC sets out all of the requirements that buildings must necessarily meet. Of course, these requirements will vary between different building types/profiles having different levels of risk and escape difficulty – as a result of differences in their occupant number, occupant mobility, building height, travel distance, etc.
Pharmaceutical manufacturing facilities mainly tend to be:
- class 7-8 buildings,
(For determination of building classification, refer blog: Building Classification)
- with maximum of 2 storeys.
(For calculation of rise in storeys, refer blog: Rise in Storeys)
Therefore, here, we will focus on the clauses/requirements for this type of building profile.
1. How many exits required for a building?
Before answering this question, it’s important to understand the definition of ‘exit’ in the NCC. Any of the following building elements which lead people to a place of safety (a road or open space) are regarded as an ’exit’:
- stairway (internal or external),
- fire-isolated passageway, and
- doorway opening to a road or open space.
In addition to these, the doorway leading to another fire compartment (a safe place) to which people will flee is also described as a (horizontal) exit.
As a general rule for all building types, at least one exit from each storey must be provided to enable people to safely escape from the building in case of an emergency. Some buildings with higher evacuation difficulties for some reasons (greater building heights, larger building areas, provision of sleeping accommodation, limited mobility of occupants etc) will require more than one exit. Manufacturing facilities mainly consisting of production/process areas, warehouse, offices and technical areas tend to occupy large areas and therefore it may be necessary to provide several alternative (multiple) exits.
2. Are stairways required to be fire isolated?
Stairways serving as required exits to provide egress from upper floors may either be fire-isolated or non-fire-isolated. It depends on the number of storeys they connect. If they serve more than 2 consecutive storeys, then they must be fire-isolated. However, if in the case where a facility contains a sprinkler system satisfying the requirements specified within the code, then 3 consecutive storeys are allowed to be connected by non-fire-isolated stairways. Having the tendency to extend horizontally rather than rising in storeys, manufacturing facilities commonly do not require fire-isolated stairways.
3. Maximum travel distance to an exit
For a manufacturing facility, the maximum allowable travel distance from any point within the building to a single exit is 20 m. However, in the case where people are provided with two options (alternative exits) to escape from the building, then by travelling maximum 20 m, they need to reach either an exit or to the point of choice where they can travel in different directions to two exits – in which case the total travel distance to one of those exits can be maximum 40 m.
So basically, it looks something like this:
4. How to locate alternative exits?
The general approach is to locate alternative exits as uniformly as possible within the storey so that they can be easily accessed from all parts on the floor. While positioning two alternative exits, we need to keep a reasonable distance between them, which is a minimum 9 m and a maximum of 60 m apart, to ensure that one exit is still accessible when the other one cannot be reached in an emergency.
5. Maximum travel distances via (non-fire-isolated) stairways
It is important to ensure that in an emergency, occupants reach a safe place by travelling limited distances. With this intention, the following distance constraints are specified within the code for the escape through a non-fire-isolated stairway;
Travel Distance from Base of Stairway to Discharge Point
The maximum travel distance permitted from the base of a (non-fire-isolated) stairway to the discharge point – the doorway providing egress to a road or open space – is 20 m. However, in case two such doorways are provided at the locations which require travel in (nearly) opposite directions from stairway, then the maximum distance allowed to each one will be 40 m.
Overall Travel Distance Via Stairway
The total travel distance from any point on the floor to the point of egress to a road or open space through a (non-fire-isolated) stairway can be maximum 80 m. This overall distance includes:
- travel from any point to the stair,
- travel on the stair and,
- travel from stair to the open space.
6. When do we need horizontal exits?
In general, manufacturing facilities tend to occupy large areas and volumes due to the nature of business (such as tall process equipment, high capacity warehouse storage, etc.) and therefore they may need to be divided into fire compartments to satisfy the area and space limitations specified within the code.
(For regulatory constraints on building size, refer blog: Building Sizing)
In this case, horizontal exits – doorways connecting fire compartments – will be very effective to overcome problems associated with large areas such as excessive travel distances to exits, as they will allow people reach a place of safety (the connecting fire compartment) by travelling shorter distances.
7. Escape from technical areas
Small plant rooms are assumed to represent a low risk to people in case of emergency as they have:
- a low occupancy rate,
- short travel distances to exit, and
- only trained people inside (familiar with the room layout and potential risks).
And that is why the following concessions are made. For plant rooms, if their;
- Area is a maximum of 100 m2, the egress can be provided by a ladder instead of a stairway and
- Area is between 100 m2 and 200 m2, when multiple exits are required, then only one of them needs to be a stair and the others can be a ladder.
The ladder mentioned here must satisfy the requirements specified within the code.
8. Dimensions of exits and travel paths
In further detail, the minimum dimensions (width and height) of exits and travel paths (corridors, passageways, etc.) are set out within the code in order to allow all occupants to safely evacuate the facility within a reasonable time. For a manufacturing facility, the minimum allowed:
- width is 1 metre, along the path that people will travel through from any point within the building to a road or open space – except doorways where width may drop to 750 mm. However, for large facilities accommodating more than 100 staff, the greater widths may be required due to the higher occupancy number.
- height is 2 metres along the egress path – except doorways where the height may drop to 1980 mm (standard door frame). This is the net height to be measured clear of any projections from the ceiling such as bulkhead, beam, cable tray, light fitting, pipe, sprinkler head, etc.
However, it should be noted that this minimum height allowance does not exempt the exits and travel paths from the room height requirements specified in Section F – meaning that the unobstructed height along the travel path can drop to 2 m provided that it complies with the minimum ceiling heights allowed in Section F. For example, for a corridor or passageway, the room height cannot be less than 2.1 m; however, 2 m is allowed above a stairway or landing, as per section F.
Designing in accordance with all of the relevant codes and standards can be somewhat complex, and should be designed and certified by licensed practitioners so please get in touch if we can be of help.
Designing in accordance with all of the relevant codes and standards can be somewhat complex, and should be designed and certified by licensed practitioners so please contact PharmOut if we can be of help. (See PharmOut’s services for Pharmaceutical Manufacturers for more detail.)
If you would like to read more on similar topics, the following blogs may be of interest: