Image courtesy of Klaus Multi-Stacker
Can the DTS always be adopted as a building solution for compliance with the mandatory performance requirements?
OK, sorry lots of jargon here. What we are getting at is that in the Building Code of Australia (BCA) the Deemed-to-Satisfy (DtS) provisions may not always comply with the mandatory performance requirements in the BCA. This means that a building permit on this basis may be invalid.
What is important about the DtS is that they provide legal protection for designers and accredited / building surveyors / certifiers. The DtS provisions are typically deemed to comply and can in the majority of cases be relied on to provide certainty in the design process. So you want to be able to rely on them!
Here are some examples where the DTS may not comply:
- Clause E1.5 residential sprinkler systems – sprinkler systems designed to AS2118.4 in residential car parks with car stackers may not comply with mandatory performance requirement EP1.4.
- Clause C2.6 vertical spandrels – the physical separation of 900 may not comply with performance requirement CP2 – empirical testing has demonstrated this to be the case
- Clause C3.2 openings in external walls of (multi-storey) residential buildings in internal corners where the apartments are separated by fire resisting bounding construction (compare this to Clause C3.3 where the openings are in different fire compartments)
- Specification E2.2b DtS smoke exhaust systems with mandatory performance requirements EP2.1 and EP2.2.
- Specification E2.2a AS1668.1 zone smoke control systems with mandatory performance requirement EP2.2
- Clause C3.4 -/60/- Automatic closing fire shutters with mandatory performance requirements CP2
- Definition A1.1 mezzanine is not a storey – therefore no exits, no fire hose reels, no exits signs, no emergency lighting required with the mandatory performance requirements DP4, EP1.1, EP4.1 and EP4.2.
Do you need as the designer need to do anything under the Building Regulations 2006?Under the Building Regulations 2006 probably not, it is really up to your accredited / building surveyors / certifiers to advise you of any issues. Where you may be most exposed is under your S28 Designer Duties in the Occupational Health and Safety Act 2004.
Under the Building Regulations 2006 as designers you do need to be aware of some limitations in the BCA and ensure you design within those limitations. For example:
- Each of the referenced Australian Standards in the BCA has a scope of limitation e.g. AS1684.1- timber framing code is limited to certain size and configurations of buildings, AS2870-1996 Residential Slabs and Footings – Standard does not include design details for Class P sites.
- There are certain parts of the BCA where there are clauses that anticipate issues with unusual conditions e.g. Clause E1.10 Provisions for special hazards for fire fighting, E2.3 Provisions for Special Hazards for additional smoke hazard management measures, E1.5 Requirement for Sprinklers Occupancies of Excessive Hazard.
The easy ones to pick up are the unusual issues on unique projects. Where it gets tricky is the day to day projects where the line is blurred. Here are 4 rules of thumb for picking up the “Danger Will Robinson signals”:
- Is there a significant crossover with OH&S?
- Is there a common law duty e.g. for children, the aged, people with disabilities?
- Is it clearly an anomaly for this type of building?
- Do you think this could have reasonably be anticipated as being applied by the original authors?
The key issue at the end of the day is that if the permit or certificate is issued outside the scope of the Regulations it is not the designers who suffer, but our end clients, the owners, who don’t get to rely on a valid permit or certificate for the works!
Tags: Building Permits, Building Regulations 2006, DTS, OH&S
[...] think this is a classic case of the solutions in the Deemed-to-Satisfy provisions not meeting the mandatory performance requirements. But they are [...]