Monarflex Gas Control Systems

Manufacture, In house design packages, directly employed installers & guarantees for the "Life Of The Building" 

Overview
Monarflex gas control systems are designed to prevent the ingress of dangerous gases into new
build projects. This section describes the systems and explains how to design and install them.
Icopal Monarflex Geomembranes Ltd is the UK’s leading manufacturer of reinforced polyethylene
construction membranes, including the outstanding Monarflex Geomembranes’ multi-layered gas
barriers RAC and Reflex Super. The gas barriers are central to the gas control systems and can be
complimented by Monarflow gas vents, pipe sealing ('top hats') and our unique membrane welding method.

Gas Contamination: The Problem
Gas is generated underground in many different conditions.

For the most part it does not constitute a hazard, as gas which percolates to the surface dissipates under normal atmospheric conditions, preventing dangerous concentrations from developing. However, when buildings are constructed on gas contaminated land, gas can seep into buildings through openings, construction joints, cavities and service penetrations to reach dangerous concentrations. Gas flows into buildings as a result of:

  • The pressure of ongoing gas production
  • The stack effect 
  • The wind
  • Ground water movement 


The more common occurring gases for which protection is required:


Methane (CH4)

  • RAC or Reflex Super membrane is required & joints must be welded
  • Main sources - Landfills, Mine Workings, Wetlands, Sewers, Gas Mains, Fly Tipping
  • Explosives between 5% (LEL) - 15% by volume (v/v)
  • Ability to migrate considerable distances
  • Lighter than air
  • Small molecular size

 

Carbon Dioxide (CO2)

  • RAC or Reflex Super membrane is required & joints must be welded
  • Main Sources - Landfills, Mine Workings, Wetlands, Sewers, Gas Mains, Fly Tipping
  • Human Respiration affected with levels above 0.5% v/v - 2.0% v/v
  • Carbon Dioxide content of 25% v/v is fatal
  • Soluble in polyethylene
  • Heavier than air

 

Volatile Hydrocarbon Vapours (VOC's)

  • RAC membrane is required & joints must be welded
  • Produce Hydrocarbon vapour
  • Main sources - Diesel, Petrol, Solvents etc.
  • Remnants of previous use - Petrol Filling Stations, Industrial Sites etc
  • Flammable / Toxic / Unpleasant Odour
  • Eats through polyethylene and jointing tapes

 
Radon 

  •  A radioactive gas associated with increased levels of cancer.

 

Other hazardous gases include carbon monoxide, hydrogen sulphide and hydrogen.

Products

RAC Gas Membrane

Reflex Super Gas Membrane

Monarflow 27 Passive Venting System