Phone 0800 030 4391
- AIR TIGHTNESS CONSULTANCY & TESTING
- ENERGY, SAP, EPC, DEC & SBEM
- BREEAM & CODE FOR SUSTAINABLE HOMES
- ACOUSTIC CONSULTANCY & TESTING
- AIR SEALING & FIRE STOPPING
- THE COMPLETE PACKAGE
- HRS Air Tightness SUMMARY
- Air Tightness Homepage
- Air Tightness - a Definition
- Part L Regulations - October 2010
- Part L Glossary
- Commercial Benefits to the Building
Owner & Client
- Information for the Client
- Information for the Architect
- Information for the Main Contractor
- Information for the Building Services Consultants
- Information for Material, Plant &
- Information for Building Control
Officers & Approved Inspectors
- Design Review
- Site Advice Visits
- Contracting Work
- Air Tightness Testing
- Air Test - Domestic Dwelling
- Air Tightness Consultancy
- SAP Ratings
- SBEM Ratings
- Example Air Tightness Test
- Smoke Test
- Thermographic Surveys
- Energy Usage
- Case Studies
- Technical Info Packs/Video Downloads
- Brochure Request/Download
- Frequently Asked Questions
- Theory of Air Tightness
- Air Tightness - Related Services
signup to our newsletter
Information for the Building Services Consultants
Poor Building Envelope Performance - Case Studies >
Advice & Quotation >
Head Office: Sheffield
Southern Office: Swindon
Regional Air Testing Bases Across the UK
Phone: 0800 030 4391
Golden Rules to Ensure Part L is Met
Ventilate right – the main contractor should build the envelope tight. This will enable the design, specification and sizing of the heating and ventilation system to be carried out with confidence. Natural ventilation openings should be fully controllable and therefore offer a reasonable standard of air tightness in the closed position. Check the envelope area is correct.
FREQUENTLY ASKED QUESTIONS
What British Standards are air leakage pressure tests carried out to?
ATTMA TS1 Measuring Air Permeability of Building Envelopes BS EN 13829:2001 Thermal Performance of Buildings: Determination of air permeabil-ity of buildings – Fan pressurisation method.
How can air permeability standards be expressed as air changes per hour – ach at a test pressure of 50 Pascals?
For a moderately sized single storey building which complies with Part L, Qleakage = <10m³/(h.m²), the average ventilation rate will be approximately 0.2ach. The ventilation rate in ach can be approximately estimated as A/(6*S) ach where A = Area of walls, roof and ground floor and S = area of walls and roof.
What is the heat loss due to air leakage?
Qleakage = rCp * V * n / 3600 W/K where rCp heat capacity of air, V volume of building m³ and n is the ventilation rate in air changes per hour - ach.
What are typical levels of savings in terms of energy usage?
For an industrial building with a floor area of 5000m², currently built without air tightness considerations, air permeability can be >14m³/(h.m²). This equates to a hole in the roof of approximately 5m²!
If the air permeability can be reduced to 8m³/(h.m²), which comfortably passes Part L, then the energy saving could equal >60,000 kWh per annum.
NOTE: Current best practice for industrial type buildings in regards of air tightness is an air permeability figure of 2m³/(h.m²).
How can complicated service penetrations be sealed?
Services can be routed through ducts inside the building envelope. Sealing multiple service penetrations is awkward but similar principles to those used to seal penetrations through fire walls and plant room slabs should be used.
How can the flow rate for the air leakage pressure test be specified in terms of the size of the fan?
ATTMA TS1 states that the fan should be able of achieving >80% of the required air flow rate at 50 Pascals pressure difference.
HRS Services are able to provide estimations for a building’s heat loss associated with uncontrolled ventilation and associated costs and potential savings by altering designs. HRS have close links built up with Sheffield University staff and have access to a vast range of skills and laboratory resources. If HRS and Sheffield University can’t help you directly, HRS will certainly offer what advice we can.
Air Tightness - Case Studies
Click headings to read more
Article from Building Magazine published 12.08.2011
Tightest building in UK Air test result <0.5 m³/hour/m², HRS involved throughout
IKEA employed the UK's largest fan to check the air tightness of its Glasgow store
A Complete Solution For Investigating, Analysing Problems and Providing Solutions