Part L Changes

From 6th April 2014 Part L 2013 superseded Part L 2010

What does this mean for you?

The changes to Part L of the Building Regulations have resulted in a requirement for a further 9% reduction (aggregate) in carbon dioxide emissions in order to achieve Part L compliance, and therefore increase construction cost.

The 9% improvement applies to England only. Wales, Scotland & Northern Ireland will be issuing their own versions of Building Regulations over the coming months.

In Wales the new target is a 20% improvement over 2010 which is coming into effect on 31st July 2014. In addition to this there will be TPEC (Target Primary Energy Consumption) measured in kWh/m2. Also the 1000m2 threshold for consequential improvements to energy performance has been removed for extensions (applies to buildings in Wales).

Does this apply to your project?

Where a building notice, full plans submission or initial notice was given to a Local Authority or Building Control Body before 6th April 2014, the provision of Part L 2013 will not apply provided work commences on site before 6th of April 2015.

What should you do?

In summary, in order to ensure future developments can be built under Part L 2010, sites must have been registered with Building Control before 6th April 2014. In addition, we reiterate that works on site will need to commence before 6th April 2015.

The following are considered to be classed as commencement of work:

  • Excavation for strip or trench foundations or for pad footings
  • Digging out and preparation of ground for raft foundations
  • Vibroflotation (stone columns) piling, boring for piles or pile driving
  • Drainage work specific to the building (s) concerned

The following are NOT considered to be classed as commencement of work:

  • Removal of vegetation, top soil, or treatment of contaminated land
  • Demolition of previous buildings on site
  • Dynamic compaction
  • General site servicing works (temporary roads for example)

Key changes in Part L2A 2013 (new buildings other than dwellings):

Part L 2013 (and supporting docs) prescribes maximum values (not to be exceeded) for certain components of the building. Major changes are:

  • Specific Fan Power – Of particular note is the ventilation system specific fan powers, which have been significantly reduced from the 2010 recommendations.  This will impact on plant sizing (i.e. AHU/fan selections), plant component selections (i.e. requirement for reduced coil and filter resistances), and is likely to result in a requirement to oversize fans and speed control them to achieve maximum efficiencies.  More significantly, the reduction in SFP’s will result in a requirement to increase duct cross sectional areas in order to reduce system resistances, therefore impacting on void depths and riser sizes.
  • Lighting Efficiency – the minimum efficiency of lighting has increased by 9% (from 55 luminaire lumens per circuit Watt to 60). This will require a greater utilisation of modern lamp sources such as LED lighting which are becoming more cost effective, however are still more expensive than fluorescent.  The way that lighting efficiency is being calculated has been altered. Previously lighting efficiency solely related to light fittings, within the new Part L lighting efficiency includes all the light fittings within the room and thee lighting controls installed as well. Therefore lighting controls cannot be an afterthought, to ensure compliance with the required lighting efficiency they need to be included with the initial design of a project and cannot be subsequently value engineered out.

The lux levels have to be entered for each room type for Part L 2013. To be clear Part L 2010 was based on luminaire efficiency, lux level remained the same in the actual and notional building based on the NCM room activity. This is introduced to limit over lighting as actual installed lighting wattage is used.

As before to comply with Part L2A the building must be more efficient than a ‘notional’ building which is a building of the same size, shape and orientation as the actual building, constructed to a ‘concurrent’ specification (set standard). If the actual building is constructed entirely to this specification it should comply with this section of Part L. However, other than this specification the only change between the ‘notional’ and actual building is the glazing proportion, with the glazing being more evenly distributed in the ‘notional’ building. This will negatively impact the lighting consumption and therefore the carbon emissions of the actual building.

Compliance should in theory still be possible without the addition of renewable technology however it will need a combined effort by all members of the design team to access and reduce energy and carbon emissions. Adding insulation and improving the U-values are not a cost effective way to approach compliance. Lighting and auxiliary energy represent a significant proportion of the overall energy consumption. Daylight dimming, PIRs and use of demand control ventilation will help in achieving compliance.

Part L BRUKL and EPC outputs will be worse with 2013 as gas, electricity and other fuel carbon factors have increased.

KEY CHANGES TO THE NOTIONAL BUILDING ARE:

  • Air permeability now varies for building size but is as low as 3m³/hr per m² at 50 Pa
  • U values are improved.
  • Boiler heating efficiencies have improved
  • Additional ventilation controls have been included

The following table compares the notional building in Part L2A 2010 to Part L2A 2013:

(Those in red are the changes)

NOTIONAL BUILDING COMPARISON
PART L2A – NON-DOMESTIC NEW BUILDINGS

NOTIONAL / TARGET BUILDING

NOTIONAL / TARGET BUILDING

2010

2013

Wall – U value

0.26 W/m2.K

0.26 W/m2.K

Floor – U value

0.22 W/m2.K

0.22 W/m2.K

Roof – U value

0.18 W/m2.K

0.18 W/m2.K

Door – U value

2.2 W/m2.K

2.2 W/m2.K

Window – U value

1.8 W/m2.K

1.6 W/m2.K

Rooflight – U value

1.8 W/m2.K

1.8 W/m2.K

Window – G value

40%

40%

Rooflight – G value

43%

55%

Window – Light Transmittance

71%

71%

Rooflight – Light Transmittance

67%

60%

Air Permeability

5 m3/hour.m2 @ 50Pa

5 m3/hour.m2 @ 50Pa for building below 250 m2 otherwise it will be 3 m3/hour.m2 @ 50Pa

Heating Efficiency (Space Heating)

79.2%

91.0%

Heating Efficiency (Hot Water)

83.6%

91.0%

Cooling Plant SSEER

3.6

3.6

Cooling Plant SSEER (mixed mode)

2.7

2.7

Pump Type

Variable Speed Multiple Pressure Sensors

Variable Speed Multiple Pressure Sensors

Lighting Efficacy

55 luminaire lumens
per circuit-watt

60 luminaire lumens
per circuit-watt

Daylight Control

Yes

Yes

Occupancy Control
(Presence / Absence Detection)

No

Yes

(Manual On

Auto Off)

Power Factor Correction

>0.95

>0.95

Automatic monitoring and targeting with alarms for out of range values

YES

YES

Specific Fan Power (Central Systems including Heating & Cooling)

1.8 W/l/s

1.8 W/l/s

Specific Fan Power (Terminal Unit)

0.5 W/l/s

0.3 W/l/s

Heat Recovery Efficiency

70%

70%

Mechanical Ventilation Controls

None

Variable speed control of fans via CO2 sensors

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