Lightweight Construction

Building approvals/ building permits to construct or alter buildings issued by building surveyors/ building certifiers quite often contain elements defined in the Building Code of Australia as ‘lightweight construction’ and is nominated as an essential safety measure. Care must be taken, as not all lightweight construction is deemed an essential safety measures schedule/ determination.

Building Code of Australia

PART A1
INTERPRETATION

A1.1 Definitions

Lightweight construction means construction which incorporates or comprises –

  1. sheet or board material, plaster, render, sprayed application, or other material similarly susceptible to damage by impact, pressure or abrasion; or
  2. concrete and concrete products containing pumice, perlite, vermiculite, or other soft material similarly susceptible to damage by impact, pressure or abrasion; or
  3. masonry having a thickness less than 70 mm.

If a designer wishes to use lightweight construction in a wall system and utilise a fire resistance level of the nominated lightweight construction then the ‘element’ must comply with Part C1 Fire Resistance and Stability clause 1.8 Lightweight construction and Specification C1.8, an extract follows:

PART C1
FIRE RESISTANCE AND STABILITY

C1.8 Lightweight construction

  1. Lightweight constructionmust comply with Specification C1.8 if it is used in a wall system –

SPECIFICATION C1.8
STRUCTURAL TESTS FOR LIGHTWEIGHT CONSTRUCTION

  1. Scope
    This Specification describes tests to be applied to and criteria to be satisfied by a wall system of lightweight construction.

The following illustration depicts a protection method for a light weight construction (fire rated wall).

The following is a part extract of clause I1.1 for an Essential Safety Measure (as appeared in BCA 2013) known as lightweight construction:

Table I1.1 SAFETY MEASURES – BUILDING FIRE INTEGRITY

Safety Measures BCA Provision for Determining Standard of Performance
Building elements required to satisfy prescribed fire-resistance levels D1.12

Essential Safety Measures Audit – Lightweight Construction

An essential safety measures auditor must have a very good understanding of the fire separation requirements incorporating lightweight construction under the Building Code of Australia. When performing an essential safety measures inspection to ensure fire safety compliance, the auditor must be able to recognise that a painted plasterboard wall is actually lightweight construction that requires a fire-resistant level and that penetrations in the wall are required to be fire stopped with an approved FRL product (fire stopping). The results of a lightweight construction wall inspection must be recorded in the essential safety measures logbook to ensure signing of the Annual Statement, Annual Certificate Compliance, Annual Fire Safety Statement or Annual Occupiers Statement.

Without adequate BCA knowledge, an essential safety measures auditor would have no idea when inspecting a wall whether the building surveyor/ certifier nominated the wall (lightweight construction) to have a FRL due to its location, type of construction of the building, classification or use to which part of a floor in a storey has been nominated for.