Above Ground Considerations

Material Specification

The product standard EN 877, paragraph 4.6.1, details the specification required for the internal and external coating of lightweight cast iron pipes above ground level. Internal coatings for the Harmer SML system have been tested in accordance with 5.7.2 of EN 877 for salt, waste and chemical resistance. External coating is a primary coat that is not readily flammable and is free from toxic metals as per clause 4.6.3 of EN 877.

Harmer SML above-ground pipe is provided with a two-part epoxy coating to the internal surface as an Ochre colour to a minimum thickness of 120 μm. The external surface receives an anti-corrosion primer coating as Red (RAL 3009) to a minimum thickness of 40 μm.

SML fittings are internally and externally coated to the Red specification, dip applied to a thickness of 40μm and therefore complies with the standard.

Pipe connections can be made with either Stainless Steel couplings as in accordance with EN 10088-2 and EN 10088-3 for all grades of austenitic steels or Ductile Iron couplings as defined in table 3, paragraph 4.5.2 of EN 877 stating a minimum tensile strength of 420 MPa and maximum Brinell hardness of 250HB.

Both Stainless Steel and Ductile Iron couplings incorporate Elastomeric EPDM gasket seals as in accordance with BS EN 681-1.

Environmental Conditions

Fire protection should have some consideration for above-ground applications. The weak area is the building structure in respect of wall and ceiling penetrations. Reference should be made to EN 1366-3.

It is a common occurrence to incorporate plastic waste pipe to a typical SML cast iron system but that constitutes a vulnerable area whereby a non-combustible and combustible material are combined as a mixed system. Adequate protection should be considered.

Although impact sound is relatively low for SML, further acoustic protection may be required depending on the environmental use of the habitable area. The European Standard EN 14366 gives two separate values for airborne sound and structure-borne sound. Airborne sound is measured in the room where the pipeline is installed, structure-borne sound is measured on the other side of the wall to which the pipeline is fixed. When standard brackets are used with rubber inserts, a maximum of 45 dB(A) airborne sound pressure can be created when considering a flow rate of 2 l/s which corresponds to a typical toilet flush. There is a benefit if a pipe bracket with acoustic decoupler is fitted since that would offer structure-borne sound characteristic level of less than 10 dB(A), that is quieter than falling snow!

Pipe Installation

Vertical pipework must be supported with a load bearing bracket to carry the weight of the pipe and its contents. For a 100mm diameter pipe, a stack pipe support bracket is required on every fifth-floor area. In addition, Harmer optimal brackets should be installed at 2m maximum centres or alternatively the Harmer Ductile Iron brackets can be incorporated at 3m maximum centres.

Galvanised steel threaded nut M8 or M10

Elastomere (EPDM)

A2 stainless steel housing Galvanised steel threaded connection (wrench size 17mm)

Woco patent EP 1 061 303 B1