PO

Gas protection

Gas Barrier SystemPassive gas

protection system

l Gas barriers

l Ventilation system

l Installation service

l Integrity testing

Unprotected

Protected by PAGeotechnical

PAG gas protection systemPAGeotechnical’s gas protection system has been developed to enable Developers and Contractors to protect new buildings against gasses contained in contaminated land. PAG’s system is suitable for installations ranging from housing to industrial and commercial/retail, and PAG utilises products that conform to all current guidance. PAGeotechnical also offers a full planning and installation service.

The gas contamination problemIf buildings are constructed on or near gas contaminated land there is a risk that hazardous gasses may penetrate the building and concentrate if not allowed to escape. Gasses which may cause problems include carbon dioxide, methane, hydrocarbon vapour and radon. Common causes of their presence include brownfield sites, landfill and natural occurrence such as peat.

The PAGeotechnical answerAt the heart of the PAGeotechnical system is a gas barrier membrane, in combination with a ventilation system to remove gas. The installation and testing of these products is a skilled process and PAGeotechnical can provide this skill if required.

A range of gas barriers is available, and PAG will be pleased to recommend the appropriate specification. The system provides passive protection without the need for monitoring or mechanical equipment and so is ideal for housing and small industrial and commercial units. For large installations or those requiring additional protection, please ask for details of PAGeotechnical active and supported systems.

PAG has developed a range of high quality products to provide both barrier and venting. Gas barrier can be supplied in preformed sections - especially useful to speed up installation on housing sites. Alternatively sealing can be carried out on site.

HousingBarriers can be applied to both ground bearing concrete slab floors and suspended beam and block floors to meet NHBC Amber 1 and Amber 2 requirements.

Ground bearing concrete slabThe slab is poured directly on to the gas barrier, below which is a venting layer of 200 mm granular material, or PAG 25 void former, which provides the most effective venting and forms a more stable substrate. Ventilation paths must be provided from the venting layer to atmosphere via a trench with granular fill, or air bricks.

Suspended beam and block floors.Gas barrier is laid over the structural floor and covered with a screed. The sub floor can be ventilated by air bricks.

Commercial and industrialGas barrier is applied in a similar way to a housing project, i.e. a slab is poured on to a gas barrier which has a venting layer below it. However, the venting system must accommodate the larger scale. Typically this can be a network of perforated or slotted pipes within a granular layer, or strips of PAG 25 void former installed within a granular layer.A

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KeyPAG barrier / void former

Air

Contaminating gas

Working with the PAG systemAs with all gas protection products, PAGeotechnical’s gas barrier system must be installed to conform to Building Regulations and quality assurance standards. All installations should be in accordance with guidance contained in BRE414.

PAGeotechnical offers a full installation service, or can assist and advise as required. PAG’s skilled installers use prefabrication techniques and specialised on site welding to ensure installation is as efficient as possible. We can also provide an integrity testing service.

PAG Standard Gas Barrier

• Reinforced LDPE membrane including aluminium foil.

• Extremely low gas transmission.

• Exceeds DPM standards.• Weldable.• BRE approved.• Suitable for use with

hydrocarbon contaminated soils.

PAG Super Gas Barrier

• Five layer process membrane.

• Exceeds DPM standards.• Extremely low gas

transmission.• Weldable.• Aluminium foil core.• Meets BS for DPC.

PAG 25 void former

• Made from cuspated High density Polyethylene (HDPE).

• High strength and crush resistance.

• Available as fully wrapped or single-sided geotextile.

PAG cross linked butyl sealant

• Suitable for joining polyethylene membranes.

• Very low gas transmission.

Installation procedure

When a venting layer is required, this should be installed first and connected to collector pipes and vents.

Installation of gas membrane is critical to the success of the system. Where possible the whole area should be covered with membrane in one process and sealed by welding or use of double sided gas jointing tapes. Penetrations for services, and junctions, must be sealed. Preformed ‘Top Hat’ units and adhesive membrane sections are used for this purpose.

The PAGeotechnical range

Service pipe

PAG cross-linked butyl sealant

PAG gas barrier

PAG 25 void former

Pre-formed ‘Top Hat’

Steel stanchion

PAG adhesive gas resistant membrane

Integrity testing

The final stage of installation is integrity testing which ensures the system is safe. A test gas mixed with air is introduced under the membrane via a special fitting. Then, using special detectors, the entire lined area can be ‘swept’ to identify any flaws. Once sealed and retested the completed membrane is issued with a Certificate of Integrity.

Gas protection

Containment

Bioremediation

Geosynthetics

Root barriers

PAGeotechnical Ltd.,Perth House,Corby Gate Business Park,Priors Haw Road., CorbyNorthants. NN17 5JG

Telephone: 01536 740040Fax: 01536 740044Email: office@pageo.co.ukWeb: www.pageo.co.uk

Technical data

Gas barriers

PAG Standard** PAG Super*

Composition Scrim reinforced polyethylene and aluminium.

Min. weight/unit area 370 g/m2 415 g/m2

Minimum thickness 0.40 mm 0.46 mm

Tensile strength 10.5 kN/m BS 4415 Pt 2 9.47 kN BS EN ISO 10319

Methane permeability < 0.001 ml/m2/day < 0.005 cm3/h/m2

Petrol vapour transmission 1.58 g/m2/hr (ASTM D5866) Not tested

Moisture transmission < 0.01 g/m2/day < 0.01 g/m2/day

Radon improvement factor 500-1 500-1

CBR na 708 N

Roll size 2 x 50 m 1.2 x 50 m

Suggested Specifications “The gas barrier shall be [PAG Super Gas Barrier]* [PAG Gas Barrier]** loose laid on to prepared substrate. The membrane shall contain aluminium foil encapsulated in polyethylene and be reinforced with polyester scrim, minimum thickness [0.46 mm]* [0.40 mm]** methane transmission less than [0.005 cm3/h/m2]* [0.001 ml/m2/day]**. It shall be sealed with cross linked butyl gas tape or welded to quality assurance standards.”

Cross linked butyl sealant

Density 1.6 g/cm2 Service life (predicted) > 20 years

Elongation at break 220% Service temperature range -4C – 110C

Force to compress by 20% 220 N Shrinkage < 0.5%

Movement accommodation 15% Shear strength 17.1 N

Moisture vapour transmission 0.24 g/m2/24h Slump Nil

Paintability Good Tack Very good

Resistance to mould Good UV resistance Very good

PAG 25 Geocomposite voidformer

Values are typical, with the exception of thickness, which is nominal. Typical indicates the mean value derived from samples taken for any one test as defined in the BS EN ISO standard - usually the mean of five samples. Nominal is a guide value.

Properties Performance

Geotextile type Geotextile material

Non woven & heat-bonded Polypropylene

In plane gas flow at 20 / 100 / 200 kPA

20 / 19 / 18 l/s/m width

Geotextile pore size 85 microns EN ISO 12956 Thickness at 2 kPa 25 mm BS EN 964-1

Core material Single cuspated HDPE (High Density Polyethylene)

Roll size / weight 0.9 x 50 m / 67.5 kg

Tensile strength MC/CD 8/9 kN/m EN ISO 10319 Suggested Specification “Cuspated HDPE (High Density Polyethylene) drainage core former thermally bonded to a geotextile filter.”

CBR puncture resistance 1.5 kN EN ISO 12236

Compressive strength 180 kPa

Shear strength 1 kN prEN ISO 13426-2