For many building products or systems, there are no relevant standards or published criteria. In these situations it is necessary to decide what an appropriate standard or criteria ought to be.
There are many means for determining performance criteria for a building elemtn, product or system.
One method is to search for standards or test methods for the same or similar types of products and write up a chart of the standards or methods and assess each of their suitability.
For more demanding situations (where a risk score is high) it may be necessary to develop a new test method or criteria from scratch. This will usually require the author to develop a new test method,that can be used to verify compliance with the relevant performance requirement(s) of the New Zealand Building Code.