Creating a Specification 44 Report

What Is a Performance-Based Design Brief?

When your Class 1 building can't meet standard energy efficiency requirements but you have an alternative approach that works just as well, you need to prepare a Performance-Based Design Brief (PBDB). For thermal performance, this means demonstrating your building meets the heating, cooling, and energy load limits in Specification 44, even if your design doesn't follow the usual NatHERS or elemental provisions.

The Four-Step Process

The following 4 steps are those prescribed by the ABCB Performance Solution Process documentation. While they are identified as 4 clear steps, they may be not represent steps in typical modelling processes as steps 1 - 4 can all be undertaken at once. However, please note that some approved authorities expect these steps to be clearly identified in your project communication, so early engagement is critical to understand what is required on a project by project basis.

1

Prepare Your Design Brief

Start by communicating with your client, the building surveyor, and any relevant consultants. Document exactly what you're proposing and why the usual NatHERS or elemental provisions doesn't work for your project. For H6P1 and H6P2, this means explaining your alternative approach to achieving thermal performance and energy efficiency.

Your brief should clearly state which Performance Requirements you're addressing (H6P1 for thermal loads, H6P2 for domestic services efficiency) and how you'll prove compliance. Get everyone to agree on your approach before proceeding, this agreement is crucial and saves time later.

2

Carry Out Your Analysis

For H6P1, calculate your building's annual heating, cooling, and total thermal energy load limits using appropriate software or calculation methods.

For H6P2, calculate the energy consumption of your proposed heating, cooling, hot water, and lighting systems. Compare this against the baseline systems specified in the code (3-star heat pumps, 5-star gas water heater, standard lighting). Your total must not exceed 70% of this baseline.

3

Evaluate Your Results

Compare your calculated loads against Specification 44 limits for your climate zone. Your building must meet all three limits: heating load, cooling load, and total thermal energy load. If you're close to the limits, check your calculations and assumptions carefully.

For domestic services, verify your total energy value is below the 70% threshold. Document how each service contributes to the total and where you've achieved savings compared to the baseline.

4

Prepare Your Final Report

Create a clear report showing:

• Project details and why you needed a Performance Solution

• Your calculation methodology and assumptions

• Results compared to Specification 44 limits

• How your domestic services achieve the required efficiency

• Any special conditions or limitations

Include simple tables comparing your results to the requirements. For example: "Heating load: 45 kWh/m²/year (Limit: 50)" makes compliance immediately clear

Key Tips for Success

Keep it proportionate. A Class 1 building doesn't need hundreds of pages of analysis. Focus on clear demonstration of compliance with the quantitative limits. Early consultation with your building surveyor helps identify their specific requirements and prevents rejection.

Remember that both H6P1 and H6P2 must be satisfied together. Your building envelope performance and services efficiency work as a system. Document this clearly in your brief, showing how your overall approach delivers an energy-efficient home that meets the Performance Requirements through an alternative but equivalent pathway.

This streamlined process, following the ABCB's four-step framework, ensures your Performance Solution is properly documented, assessed efficiently, and ultimately approved.