The disadvantage of using Part 4 is that it generally over-engineers building components, the span tables are less comprehensive and can be less economical to use than Part 2, so this should be considered when deciding which part to adopt. Part 2 has supplementary span tables on CD that requires more input to calculate timber sizes but delivers more choice. The simplified version is popular for its hard copy span tables and minimal information is required to determined spans. Part 2 is a lot more complex in relation to bracing calculation and requires the raking forces to be determined and the calculation of bracing expressed in kilo Newtons per metre designed to counter that force. To assess the amount of bracing a building requires under Part 4 only requires four steps, the bracing units are expressed as type A or type B and a simple table will indicate how many units are required. There is a limit placed on the maximum roof pitch in both documents of 30 degrees for Part 4 and 35 degrees for Part 2. The maximum width of a building designed under Part 4 is 12m where Part 2 can be used for building widths up to 16m and maximum external wall heights are 2.7m and 3m respectively. These Span Tables have been prepared in accordance with standard engineering principles, the relevant test reports and Australian standards, ie: AS1720.

Part 4 can only be used in the two lower wind classifications of N1 and N2 where Part 2 covers wind classifications up to N4. as shown in these tables, and installed in accordance with the provisions of this Design Guide, complies to the uilding ode of Australia. For further information on LVL go to Figure 6: Branding for LVL products n n n n n Ceiling load width (CLW) Ceiling load width (CLW) is the contributory width of ceiling, usually measured horizontally, that imparts ceiling load to a supporting member.

The criteria in both versions are specifically for conventional timber-framed buildings of one or two storeys. the span tables in this manual, LVL must attain a Modulus of Elasticity of 10 MPa. A double 3 1/2 × 5 1/2 lvl beam can allow span up to 10 feet far distance used for residential building or projects. But there are differences between the two Standards that users must be aware of that places limitations on the simplified version. A double 5 1/2 LVL is made by laminating of two 1 3/4 inches or 40mm thick and 5 1/2 deep LVL. Part 4 is referred to as the ‘Simplified’ version.Īs the name suggests, Part 4 being the ‘simplified’ version was developed as a more user-friendly document than Part 2.

Part 2 and 4 are used in non-cyclonic areas and Part 3 is designed for the cyclonic areas of northern Australia. The other three parts provide building practices and procedures that assist in the correct specification and determination of timber members, bracing and connections.This is the document commonly used by engineers Part 1 relates to design criteria that can be used as a basis for the preparation of span tables and design data for the other parts.AS 1684 Residential Timber Framed Construction has four parts:

Lvl beam span tables australia