Introduction

Back in March I talked about the need for good product compliance information and the proposed new mandatory requirements for building product compliance. Since then, we have seen a bit more information on what is being proposed with MBIE consulting on the nature and content of the proposed regulations. At this stage there is no public information available on what the words in the regulations will be — we can only hope that we will see the draft words before they are finalised.

Whatever the detail of the regulations, what is inevitable is that there is going to be a major focus on providing compliance information. This will expose some issues in the Building Code and its system and how it relates to building products and systems. Up until now these issues have only needed to be dealt with by product certification (CodeMark) bodies, appraisers such as BRANZ and companies providing product compliance support. With potentially thousands of product suppliers needing to provide mandatory information, we need to develop some consensus on how to approach the issues so as not to create confusion among the users of the information such as building officials and designers. There is also a case for MBIE to 'tidy up' the Code system to make product information support easier to supply and consistent with the structure of a performance-based building code. In this blog post I will describe the code and how it relates to products and over the next few blogs I will identify some of these issues in this application and propose some improvements.

Note: When I refer to the Building Code in this series of blogs, I am referring to the Code itself, that is the regulation made under the Act (which contains objectives, functional requirements and performance clauses), not the combined Code, acceptable solutions, verification methods and cited standards which I call the code system. Unfortunately, MBIE has taken using the title “Building Code” when it should use the term system. We need to remember that we have a performance based code to facilitate innovation. Conflating these two constructs creates the impression that the only way of complying with the Code is through an acceptable solution, verification method or cited standard.

Building Act and Code 101

Our building regulation is focused on regulating building work. There are three 'legs' to this regulation: compliance with the building code for all building work, contractual obligations for residential building work over a certain value (currently $30,000) and licensing obligations for restricted building work.

At its fundamental legal basis, the code is the technical performance standard for building work. Products are only regulated when they are used in a particular instance of building work (this particular building and this part of the building). The changes made to the Building Act modify this to the extent of requiring compliance information.

The Code has a number of 'subjects' to which the performance obligations apply — these can range from 'buildings' to 'materials' and all points in between such as building elements, external walls, fire cells, structural systems and roofs. You can identify the subjects by looking at the relevant performance clause, for example clause D2.3.5 says “Mechanical installations on accessible routes shall” — here the subject of the clause is mechanical installations (of course the obligation only applies to those mechanical installations on accessible routes).

Steps in establishing what code clauses apply and the extent of compliance

The first step in establishing what code clauses are relevant is to identify the functional role of the product and a code clause. For example, a cladding is part of the system to deal with external moisture so some performance clauses with E2 — External Moisture are relevant. Some products have a functionality that does not relate to a code obligation but have an obligation arising from where they are used. For example, a (non-bracing) lining on an internal wall generally does not have a functionality that relates to a code clause but may have obligations relating to being a surface lining in certain buildings and parts of buildings (C3.4 (a)).

The next step in establishing what compliance of a product requires involves developing a relationship to the 'subject' of a code clause. Most products are materials so that is easy — F2.3.1 (Hazardous Building Materials) applies. Most products are not buildings so for those code clauses that relate to buildings, a product can only "contribute” to the compliance clause i.e the product itself will not mean that the building will comply with that clause but the product will contribute to compliance.

The final step is to ensure that the probability of occurrence of a 'hazard' or event the code is trying to manage relates to the use of the product. For example, an external cladding (which is also a building element) generally has some obligations relating to B1 - Structure. The loading conditions (“likely to affect the stability”) under B1.3.3 generally include wind (h) and earthquake (d) among others depending upon the configuration. Explosion (k) is in most cases not likely to affect the stability of most building elements (but may for example if the building was an ammunition magazine).

Compliance with B2 – Durability is automatic as long as there is a performance clause identified.

Identification of the scope for which compliance is claimed

Having established which code clauses apply, the next stage is to establish the scope for which compliance is claimed. In general, most products may comply in general conditions but not all. Constraints often relate to wind, exposure and seismic limits. Generally the scope is constrained by the available evidence of compliance.

Outcome

The processes described above leads to the ability to make a statement “this product complies with performance clauses ….. when used in the following zones ….” (of course these claims need to be back by evidence).

Next month's blog

What I have described above requires a high degree of judgement, and inconsistencies in the drafting of the code make the task more difficult than it first appears. In the next few blogs, I will look in more detail at some of these difficulties.