BS ISO 9349-2017 pdf free download.Ductile iron pipes, fittings, accessories and their joints — Thermal preinsulated products
4 Technical requirements
4.1 General
A preinsulated pipe (or fitting) is generally manufactured by injection moulding the polyurethane foam thermal insulation layer between the ductile iron conveying pipe (or fitting) and a casing which provides the external protection against mechanical damage and moisture ingress.
The external diameter DR of a preinsulated pipe or fitting is the external diameter of the casing.
4.2 Conveying ductile iron pipes and fittings
The conveying pipes and fittings shall comply with the requirements of ISO 2531 for water applications and of ISO 7186 for sewage applications, or, by agreement between manufacturer and purchaser, withthe requirements of relevant national standards.
Prior to thermal insulation application, the external surface of the conveying pipes and fittings shall be dry and clean.
4.3 Casing of preinsulated pipes
Casings shall be made of polyethylene (HDPE), poly(vinyl chloride) (PVC) or steel. Their characteristics shall comply with the requirements of Table 1. For above ground applications, HDPE and PVC casings shall be resistant to ultraviolet radiation. All steel casings shall be externally coated (e.g. galvanized);
the external coating shall be adapted to the application (above or below ground) and shall comply with an international or national standard, or an agreed technical specification.
Prior to thermal insulation application, the internal surface of the casings shall be dry and clean.
The variation in the casing external diameter DR during injection moulding of the thermal insulation shall not exceed +2 %.
4.4 Casing of preinsulated fittings
4.4.1 General
The external protection of fittings shall consist of preformed casings which shall be fabricated by welding several elements cut from the same HDPE or steel casings as those used for preinsulated pipes (see 4.3).
After welding and before moulding the polyurethane foam, the preformed casing shall be centred with respect to the conveying fitting. The internal surface of the preformed casing shall be dry and clean.
After the moulding operation, there shall be no leakage of foam through the welds.
4.4.2 HDPE casings
Before welding, the elements shall be cut with good precision to the required angle and both ends shall be ground.
The welding operation shall be carried out by qualified personnel, either by the hot plate method (butt welding) or by deposition of polyethylene. The difference in fluidity indexes of the added polyethylene and the polyethylene of the casing shall not exceed 0,5.
The mismatch between welded elements shall not exceed half the thickness of the casing in the direction perpendicular to the casing wall and 3 mm in the direction parallel to the axis of the casing.
The welds shall have a maximum width of 20 mm and a maximum height of 5 mm; they shall not be ground.
4.4.3 Steel casings
Before welding, the elements shall be cut with good precision to the required angle and both ends shall be ground.
The welding operation shall be carried out by qualified personnel, in accordance with ISO/TR 25901-3,and shall result in a watertight weld.
The steel casing should be externally coated, complying with an international or a national standard.
4.5 Thermal insulation
The rigid polyurethane foam thermal insulation layer shall have a regular structure of fine pores.
Specifications concerning the foam shall be as given in Table 2.
The mean thickness of the thermal insulation layer shall be as given in Tables 4 to 7, excluding the socket end of the pipe or fitting; this will give a maximum thermal conductivity of 0,027 W/(m·K) for the preinsulated pipe.
Thicker thermal insulation layers may be supplied by agreement between manufacturer and purchaser.
The eccentricity of the insulation layer, defined as the distance between the ductile iron conveying pipe axis and the casing axis, shall not exceed the values given in Table 3.
At both ends of pipes and fittings, the end faces of the insulation layer shall be covered by a polymeric sheath or a rubber ring.
4.6 Joints of conveying pipes and fittings
Joints of conveying pipes and fittings shall be flexible joints complying with the requirements of ISO 2531 or ISO 7186, as applicable.
4.7 Junctions between preinsulated pipes and fittings (on site assembly)
Continuity of the thermal insulation shall be ensured by inserting a ring of flexible foam between the end faces of the polyurethane foam layer of two consecutive pipes and/or fittings.
Continuity of the casing shall be provided by means of a rubber sleeve or a heat shrink polyethylene sleeve.
4.8 Marking
4.8.1 Ductile iron conveying pipes and fittings shall be marked in conformity with ISO 2531 or
ISO 7186, as applicable.
4.8.2 Casings shall be marked with the following:
a) the identification of the casing manufacturer;
b) in addition, for plastic casings, an identification of the material, the nominal dimensions (diameter and thickness), and the year and month of manufacture.
4.8.3 Preinsulated pipes and fittings shall bear the following information on their external cylindrical surface:
a) the nominal diameter and, for fittings, the type (e.g. for bends: B 1/8 DN…);
b) the identification of the preinsulated pipe or fitting manufacturer;
c) the year of manufacture;
d) a reference to this document, i.e. ISO 9349.BS ISO 9349 pdf download.