At a glance

• U-Value is the amount of heat energy in Watts that can pass through a square metre of element per degree Kelvin of temperature difference (W/m2K).
• As little as 0.08 air changes per hour at normal air pressure with our panels.
• 175mm thick SIP structures are insulated, achieving an excellent U-Value of 0.16W/m2K.

In detail
Energy efficiency is calculated in SAP, the Government’s Standard Assessment Procedure for Energy Rating of Dwellings and is used to measure the heat loss and carbon emissions from buildings. To achieve an energy efficient building, the three main categories of performance need to be addressed:

• U-values of building elements: Heat loss through the walls, floors, roof, windows and external doors.
• Values (Psi-values or thermal bridging) of element junctions: Heat loss at junctions in elements such as the wall to foundation junction and corner junctions.
• Air permeability of the building envelope: Additional heat loss through unplanned air infiltration, for example, around windows and external doors.

‘Fabric First’ is a popular principle taken from the German Passivhaus standard, where energy efficient buildings are created by focusing on the performance of the external envelope, before using renewable energy sources or ‘bolt on’ technology. With this approach, elemental U-Values and heat loss are driven down to low levels, resulting in the building consuming minimal amounts of energy to stay warm or cool. As SIP structures are partly insulation, excellent U-Values can be achieved with minimal wall thickness. The Low Carbon Construction Building System panels are joined together using a unique insulated jointing system, providing a more continuous layer of insulation, minimising air leakage.

To demonstrate this point, the repeating thermal bridges in timber framed buildings, caused by timber studs in the walls and roof rafters, means that it could be expected that 15% of the walls and 6% of the roof be uninsulated. In comparison, a building constructed from The Low Carbon Construction Building System, as little as 4% of the walls and 1% of the roof could be uninsulated.

The overall thermal performance of The Low Carbon Construction Building System, provided by the high performance insulation core, air tightness and low thermal bridging, means that the heating system could be significantly downsized which could save both capital and running costs. The Low Carbon Construction Building System is the perfect high performance building fabric for a low energy building requiring very little heating at all, putting it in line with Passivhaus standard.

The Low Carbon Construction Building System walls are typically 223mm deep and can achieve a U-Value of 0.22W/m2K with no additional insulation and so both meets and exceeds the Building Regulations. The Low Carbon Construction Building System can easily achieve lower U-Values of 0.1Wm2K with more insulation, which ultimately means lower running costs.

The closed cell structure of the polyurethane insulation core does not allow air movement within the wall; therefore the insulation will not sag or deteriorate over time. The jointing system used in The Low Carbon Construction Building System creates an airtight structure, as little as 0.08 air changes per hour at normal air pressure, and little opportunity for air leakage. It is important to note that buildings with very low air leakage rates require additional ventilation methods.

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At a glance

• The Low Carbon Construction Building System panels will achieve sound reductions of Rw 44dB for their internal wall solutions when tested to BS EN ISO 10140-2: 2010. This far exceeds the minimum building regulations requirement of Rw 40 dB.
• Low Carbon Construction Building System panels will achieve sound reductions in excess of Rw 45dB for their party wall solutions when tested to BS EN ISO 10140-2: 2010. This exceeds the minimum building regulations requirement of Rw 45 dB.
• Ctr: a low frequency correction factor that can be applied to the DnT,w performance measured on site.
• All our developments PASS Airtight & Noisecheck Ltd’s UKAS testing.
• Rw: a laboratory measurement of Airborne Sound Reduction.
• DnT,w: a site measurement of Standardised Weighted Level Difference.
• LnT.w: a site measurement of Standardised Weighted Sound Transmission (impact sound insulation performance.

In detail
Architectural acoustics is the science and engineering of achieving good sound within buildings and is a branch of acoustical engineering. Noise transmission from both the interior to exterior and exterior to interior of a building is measured and analysed, as controlling this allows a space to function.

With regard to external walls, there are no specific requirements for sound insulation or performance set out in the Building Regulations. The acoustic performance of an external wall is only typically considered when a significant external noise source, such as a railway line or airport, is present.

Where this is the case, the level of the most frequently occurring noise would dictate the ultimate performance of the external façade. In most cases, the window units and trickle vents are the dominant source of noise entrance into buildings.

For internal walls, the Building Regulations specify airborne sound insulation performance targets that vary depending on the area of the UK the site is located. The airborne sound insulation targets are expressed as Airborne Sound Reduction (Rw) and are based on laboratory test data.

Low Carbon Construction Building System panels will achieve sound reductions in excess of Rw 45dB for their party wall solutions when tested to BS EN ISO 10140-2: 2010 (field measurements of airborne sound insulation between rooms) on separating walls externally faced with 25x10mm timber battens, 1 layer of 12.5mm Gyproc Fireline board and one layer of 12.5mm Gyproc Wallboard.

A laboratory test on a single wall panel with 12.5mm Gyproc Wallboard on each face achieved a sound reduction of 40dB. Should the sound insulation performance need to be enhanced, multiple layers of acoustic rated plasterboard can be used, however an acoustic consultant would be needed to determine the specification for the performance requirements.

Party wall Building Regulations vary across the UK, but specify airborne sound insulation performance targets for separating/party/compartment walls, expressed as Standardised Weighted Level Difference (DnT,w) and depending on local regulations may include a correction for low frequency performance (DnT,w + Ctr).

Building Regulations specify airborne sound insulation performance targets for intermediate floors, which vary depending on the location of the site. They are expressed as Airborne Sound Reduction (Rw) based on laboratory test data. The Building Regulations also specify airborne sound insulation and impact sound transmission performance targets for separating/party/compartment floors. These are expressed as Standardised Weighted Level Difference (DnT,w) and depending on local regulations may include a correction for low frequency performance (DnT,w +Ctr). The impact sound transmission performance targets are expressed as Standardised Weighted Impact Sound Pressure Level (LnT,w).

There are no specific requirements for the sound insulation performance of roofs set out in the Building Regulations. This is usually only considered when a significant external noise source is present and as with similar lightweight structures, layers of plasterboard can help to reduce noise transmission to the rooms below.

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At a glance

• The Low Carbon Construction Building System achieves up to 75 minutes fire resistance (integrity and insulation) under LPCB Certification Standards 1208 and 1181-1.
• The LPS Certificates utilise the relevant test methods in accordance with BS 476: Part 21: 1987 and BS 476: Part 22:1987.
• Links to Hemsec Certification can be found on the Red Book Live: http://www.redbooklive.com/index.jsp
• Additional information on fire can be found on Hemsec’s BBA Certificate 06/4374, section 10: www.bbacerts.co.uk

In detail
Fire resistance is defined as the ability of an element to continue to perform despite being subjected to fire. All structures have to comply with the fire performance requirements set out by the Building Regulations but it is not difficult for SIP buildings to meet the required levels given the correct design, manufacturing standard and workmanship.

The Building Regulations have specified periods of fire resistance as well as surface spread of flame categories that all buildings need to comply with. SIP structures can be designed to meet Class O surface spread of flame and provide up to 60 minutes fire resistance. The Low Carbon Construction Building System exceeds the Building Regulations with regard to fire resistance. The system achieved up to 75 minutes resistance (integrity and insulation) under LPCB Certification Standards 1208 and 1181-1.

Ignition and fire growth and the fully developed fire are the two main stages of fire recognised and reflected in the testing and determining of fire performance of structures. The ignition and fire growth stage covers aspects such as ignitability, combustibility and the contribution of materials to the progression of fire. SIP structures do not contribute to the growth of fires as they are typically covered with non-combustible wall linings. During the fully developed fire stage, a material should contribute to the fire resistance of an element of a building.

External walls
The fire resistance of SIP walls is provided by the wall lining (typically plasterboard, although it is possible for other types of fire resistant board to be used). One layer of 12.5mm Gyproc Wallboard and one layer of 12.5mm Gyproc Fireline on 25x10mm timber battens provides up to 60 minutes fire resistance.

Internal walls
Internal walls are formed using 100mm SIP panels, combined with fire resistant wall linings to provide a fire resistance. Internal non-loadbearing walls require either no specific fire resistance or 30 minutes, achieved using a single layer of wallboard. Load bearing internal walls require 30 to 60 minutes fire resistance depending on the size and fire resistance performance of the elements they support. The required periods of fire resistance are provided with either one or two (60 minutes) layers of plasterboard.

Party walls
Party walls are constructed from SIPs. The size and type of building will influence the fire resistance requirements, although 60 minutes is typical for a party wall specification for buildings up to seven stories. It is unlikely that loadbearing SIPs will exceed this size. SIP party walls consist of two separate leaves of SIPs separated by a cavity. One layer of 12.5mm Gyproc Wallboard and one layer of 12.5mm Gyproc Fireline on 25x10mm timber battens to the external faces provide 60 minutes fire resistance and are also sufficient to meet acoustic requirements. Services that perforate the plasterboard should not ideally be installed on party walls however if they are, fire resistant pattress box inserts should be used.

Floor
The Low Carbon Construction Building System utilises SIP floors in the construction of buildings.

Roof
Roof structures do not require specific periods of fire resistance unless it forms a habitable room, where 30 to 60 minutes fire resistance is required, or the roof is part of the escape route, where the requirements are considered on a project specific basis.

Cavity barriers
Cavity barriers stop the spread of smoke through cavities and concealed spaces. The Building Regulations require that the cavity edges are closed and cavity barriers provided at compartment wall and floor junctions with external walls or other compartment walls. Each cavity barrier should provide a minimum of 30 minutes fire resistance. Cavity barriers are typically made of:

• 38mm thick timber
• Polythene sleeved mineral wool or mineral wool slab under compression when installed
• 50mm thick wire reinforced mineral wool blanket
• 12.5mm thick calcium silicate, cement or gypsum based boards
• 0.5mm thick steel
  The requirements for installing cavity barriers in a SIP structure are the same as load bearing timber studwork structures.

Where a building is constructed within 1m of a relevant or notional boundary, the specified 30 to 60 minute periods of fire resistance is required for both the inside and outside of the building. Depending on the cladding, it may be necessary to include layers of fire resistant board on the outer face of the SIP.

BRE information paper ref: IP21/10 summarises the results of a number of fire resistance tests, done on small and large scale SIP building samples, to determine the performance of SIP systems exposed to realistic fire scenarios.

As with all types of construction, smoke alarms should be fitted and tested regularly.

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At a glance

• Structural: A 10 year insurance backed guarantee as standard on all new buildings.

In detail
The Low Carbon Construction building system can be insured by most major warranty providers, as well as having CE, BBA and BM Trada certification. The SIP panels are manufactured to the highest standard under a documented factory production quality control system and have comparable durability to OSB/3 to BS EN 300.

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Within our buildings are many components that are supplied by our supply partners. All our supply partners provide their own individual warranties which vary from partner to partner and are subject to change. In this respect you will find a link to the suppliers’ website on our supply partners page where you will be able to obtain the most up to date information. Below we list a few:

• Structurally Insulated Panels: Hemsec
• Waterproofing: Prokol
• Exterior finishes: K Systems
• Windows and Doors: RFM
• Heating: DiscreteHeat and Thermaskirt
• Water Heating: SAHP
• Mechanical Ventilation and Heat Recovery: Vent-Axia
• Kitchens: Howdens
• Floor and wall Tiles: Topps Tiles
• Flooring: Karndean
• Carpets: Cormar Carpets
• Bathrooms: VictoriaPlum
• PV System: GB-Sol

Full partner list

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