Management of rainwater

Whether they are used:

  • for roofing or facade to ensure the building is watertight,
  • in rainwater evacuation systems to collect, evacuate and direct rainwater,
  • or as an element in screw-on downpipe systems for easy effective connection of rainwater harvesters,

VMZINC solutions participate in the management of rainwater in buildings and are compatible with installation of rainwater harvesting systems.

In France, harvesting and re-use of rainwater for exterior use (watering gardens, washing cars) is authorised and even encouraged (eligible for a tax credit) without any discrimination in terms of the type of materials used for the building envelope. For interior sanitary use (e.g. toilets and washing machines), re-use of rainwater is authorised without discrimination in terms of type of materials but must comply with the recommendations of the sanitary authorities (10).

France's position on harvesting of rainwater, including that having fallen from a rolled zinc roof is logical because:

  • zinc is a natural essential element, i.e. it is vital for all living organisms; for humans it is the 3rd most important oligo-element after iron and magnesium (the only “weight” of zinc is its density and not its toxicological potential).
  • The European Union has just completed a risk assessment on zinc and its compounds (all applications) and one of the main conclusions is that sources of uncontained zinc emissions (agricultural fertilisers, wear and tear of tyres, corrosion of building products, etc.) do not generate any risks for the environment (11).

For all other uses not mentioned in the French decree – especially food for fish farms or food for human consumption – an effective filtration system for this type of use must be implemented, regardless of the type of building materials used for the building in question.

(10) “Rainwater harvesting systems subject to conditions”, Le Moniteur, 6 July 2007
(11) European Risk Assessment for zinc and zinc compounds – CASE n° 7440-66-6 and EINECS n° 231-175-3