Last edited 20 Nov 2017

Main author

CatClarkson Engineer Website

BREEAM Passive design

Contents

[edit] Aim and benefits

Passive design is one of the first steps in the Energy Hierarchy:

EnergyHierarchy.jpg

The energy hierarchy aims to help designers methodically work through reducing energy demand in a building and making systems as efficient as possible prior to just installing renewable technologies. Often reducing demand and increasing efficiency are skipped in favour of "sticking some PV panels on the roof" just to meet building regulations (or enhanced regulations such as The London Plan).

Passive Design is a design technique which uses the natural movement of heat, air and light to keep internal conditions in a building comfortable. By using natural movements, there is a reduced need for energy consuming Active Design measures such as comfort cooling, heat exchangers, boilers etc.

The aim of this issue is to encourage designers to adopt measures which reduce energy consumption and associated carbon emissions, while minimising reliance on active building services systems.

[edit] When to consider

The earlier in RIBA Stage 2 this can be considered, the better. Frequently however you'll find that many of the early passive design decisions are made by designers without documenting them and that the actual report which can be used as BREEAM evidence may only be produced towards the end of the RIBA Stage along with the Stage 2 report.


[edit] Step by step guidance

[edit] Questions to ask while seeking compliance

[edit] Tools and resources

BREEAM UK New Construction 2014 Issue 5.0 Criteria - ENE 04

Blank example report template

BRE Knowledge base related articles


[edit] Tips and best practice

The evidence you need will more than likely be in a Stage 2 report, or Energy Strategy which likely will have been submitted to planning. Ctrl+F "Passive" "Lean" "Natural" to get to the right section.

If a passive design analysis is not being included in Stage 2/Energy Strategy reports, sometimes it's helpful to give engineers a blank template and tell them that essentially if they put something in each box, it'll end up compliant. This helps to stop certain aspects being overlooked without stifling their creativity in the design decision making process. An example can be found above.


[edit] Typical evidence

[edit] RIBA Stage 2 Evidence

Typically a report. A checklist of things to check the report contains:

  1. Does it cover all criteria in the compliance note relating to content (CN4 in UK New Construction 2014 Issue 1.0)
  2. Is the project name stated?
  3. Is it dated?
  4. Is the author and their company stated?
  5. Is it clearly stated that the report was produced during RIBA Stage 2? Or have you provided additional evidence to confirm that the date it was written was during RIBA Stage 2?

[edit] RIBA Stage 2/3 Evidence (Might come earlier)

The RIBA Plan of Work states that typically the engineers will produce an initial Part L report (BRUKL) during RIBA Stage 2, and a more accurate report during RIBA Stage 3. While the Part L report itself won't technically give you an energy demand reduction solely due to passive measures♦, the production of it does allow for you to know that it's time for your building physicist could produce the required evidence.

♦Many assessors will use the change in Energy Demand as stated on the Part L Report. This is technically wrong for various reasons, such as the Part L model not necessarily using realistic glazing in the notional building. Technically a building physicist should model two buildings, with the same glazing area, but with only the passive design measures varying. The baseline model should be modelled so that it is no worse than building regs values. You would then get two Part L Reports, and would need to compare the Primary Energy Demand (or CO2 emissions in BREEAM UK 2018 or International 2016) of the Actual Building for each to show a meaningful reduction.

A checklist of things to check the report contains:

  1. Do you have 2 x Part L reports, and is it clear which one relates to your actual designed building and which relates to the building without passive measures?
  2. Have both reports been produced by an accredited energy assessor or CIBSE member?
  3. If you're not confident with percentages, has the engineer confirmed the percentage reduction in energy demand (or CO2 emissions for BREEAM International 2016 and UK 2018) as a result of passive design measures?

LASTLY, DON'T FORGET CRITERIA 1: Have you awarded the thermal modelling credit?


[edit] Post Construction Evidence

  1. As per RIBA Stage 2 evidence.
  2. "As built" versions of the Stage 3/4 evidence.
  3. Site Inspection report highlighting passive design measures where possible (building form, orientation, natural ventilation possibly).


--CatClarkson

BRE Global does not endorse any of the content posted and use of the content will not guarantee the meeting of certification criteria.


[edit] Find out more

Passive building design

Building fabric

Natural ventilation

Natural ventilation of buildings

Daylighting

https://sustainabilityworkshop.autodesk.com/buildings/passive-design-strategies

https://en.wikipedia.org/wiki/Passive_solar_building_design