Explanation of Wastewater Pressure Pipe Types & Materials

PIPE TYPES 

M90SE is a black PE100 RC pipe with external twin stripes to identify the pipes application (Pressure Sewer or Stormwater) and light coloured internal layer to assist with CCTV inspection.  The three elements of the pipe CCTV pipe are co-extruded to BS EN 12210-2, using PE100 RC compounds complying to BS EN 12201-1.  The three elements of a CCTV pipe are the inner orange layer, identification stripes and the black pipe body.  These produce a single homogeneous pipe, meaning the colour layer and stripes cannot be separated in any way once the pipe is extruded.  M90SE pipe is supplied in sizes from DN100 (110mm OD) to DN 1350 (1600mm OD) using PE100 RC compounds as standard.  PE100+ compounds (Non RC pipe) is only supplied if specially ordered as M90S pipe.

CCTV PIPE has an inner light orange colour layer (See Fig. 2 - RAL 2003 in granule form) which is 15% of the pipes wall thickness.  Orange PE100 RC pipe grade material is typically used for the manufacturer of Gas pipes and it is supplied pre-coloured, ready to extrude by the compound manufacturer.  DSD Appendix Clause 3.1 states compounds may not be pigmented or coloured by the pipe manufacturer. Factory pigmented compounds or using different grades or brands of PE presents a risk of incompatibility during extrusion, typically delamination of the layers, leading to structural wall failure in the pipe and ultimately premature pipe failure.

CCTV Colour layer - Because the Orange thickness is specified at 15% of the pipes wall thickness, the colour of the inner CCTV lining varies according to the diameter of the pipe.  In small pipes DN100 (110 OD), the Orange colour is approx 1.0mm thick, it is more translucent against the black compound and appears lighter (more yellow) in colour. As the pipe size increases, the orange layer becomes thicker, translucency reduces, until it is bright orange. Full orange colour occurs in sizes of approximately DN300 (See Fig.1 below).  

This variation in colour is perfectly normal, it has no impact on CCTV inspections and demonstrates the manufacturer is correctly using a PE100 RC gas compound to make the CCTV layer. If the orange inner layer does not exhibit these characteristics, this indicates the pipe maker has likely used pigments to manufacture the CCTV inner layer on line, rather than using a certified PE100 RC Orange Gas Compound required in DSD Appendix 5A, Clause 3.3. Use of Pigmented colours poses a significant risk of delamination and pipe wall failures in the future. (See Fig.3 below, an example of pigmented pipe supplied to Hong Kong)

• Fig.1 A range of M90ES CCTV pipe from DN100 to DN800 showing the inner orange colour changing as the pipe size increases.
• Fig.2 Actual PE100 RC Orange (RAL 2003) compound as supplied by the compound manufacturer used for the CCTV inner layer.
• Fig.3 Example of FAKE CCTV pipe, coloured low density pigment for the inner layer, rather than PE100 RC Orange compound.

STRIPES are used to identify the pipes application (Pressure or Drainage, Sewer or Stormwater).  The Hong Kong Drainage Services Department (DSD) uses the European colour coding system:

• Red Brown (RAL 8012) - indicates Sewerage use (See Fig.4 below)
• Fern Green (RAL 6025)- indicates Stormwater use (See Fig.5 below)
• Single stripes around the circumference of the pipe - indicate gravity drainage (non-pressure)
• Pairs of stripes around the circumference of the pipe - indicate rising main (pressure)

• Fig. 4 Red Brown (RAL 8012) PE100 RC Pigmented Stripe Compound - Sewerage
• Fig. 5 Fern Green (RAL 6025) PE100 RC Pigmented Stripe Compound - Stormwater

Mill-Pro manufacturers our own stripe compound using a certified non-pigmented (clear) PE100 RC compound and engaging a third party compounder to pigment the compound to RAL 8012 Red-Brown and RAL 6025 Fern-Green.  Our pipe manufacturer uses this certified PE100 RC compound to stripe the pipe. This process, whilst more time consuming, ensures that the stripes are 100% compatible with the rest of the pipe body and there is no possibility of stripes peeling off the surface of the pipe. 'Stripe delamination' can lead to leaking at the joints, through electrofusion couplers.

Refer here for a case of delaminating stripe coupler leakage and the associated contract delays and legal battles over the repair costs.

M100 / M100S-Pipe is a 100% solid black wall pipe (no CCTV inner layer), the pipe is extruded from a single PE100 RC compound for M100E or with PE100 RC co-extruded coloured stripes to identify the pipes service use for M100SE.

PIPE MANUFACTURING STANDARDS

All Mill-Pro pipes and fittings are manufactured in accordance with:

BS EN 12201-1 for Compounds,

BS EN 12201-2 for Pressure pipes

BS EN 12201-3 for Pressure fittings

Drainage Services Department Particular Specification Appendix 5A

Mill-Pro Pipes and fittings also generally comply with ISO 4427-1/2 and AS/NZS 4130 for pipe, AS/NZS 4131 for PE Compounds, although are not marked as such.

PIPE COMPOUNDS

M90S / M100S Pipes are manufactured from a PE100+ association approved compound www.pe100plus.com providing 1000 hrs slow crack growth performance.  Since 2007 PE100+ compounds have been progressively superseded by PE100 RC (Resistant to Crack) compounds, which provide far superior performance and life. Mill-Pro only supplies M90S / M100S pipes by special order.

M90SE / M100SE Extreme Pipes are manufactured ONLY using PE100 RC compounds for the pipe body, the CCTV layer and the stripes.  PE100 RC compounds provide approximately 8 x greater slow crack growth resistance when compared to traditional PE100+ Compounds, for a negligible extra cost. All pipes supplied by Mill-Pro in Hong Kong are PE100 RC (M90SE / M100SE).

PE100 RC (Resistant to Crack) sometimes known as Extreme Stress Crack Resistant (ESCR) or High-Stress Crack Resistant (HSCR) compounds, are defined in the German publicly available standard: PAS 1075:2009-04. PE100 RC compounds are designed to provide lifelong resistance (>100 years) to traditional Slow Crack Growth (SCG) failures caused by rock impingement and point loading stress.

Designed for applications all commonly found in Hong Kong: Where sand bedding around the pipe is not used, where backfill material is ungraded and typically contains broken concrete or where secondary excavation (repeated excavation alongside the PE pipe, to access other services in close proximity) leaves the PE pipes without the required bedding around the pipe to prevent rocks or concrete point loading on the pipe surface.

Read more about PE100RC compounds or refer to the Borouge website on Borsafe™ HE3490-LS-H here.

All Mill-Pro Pipes and progressively our black fittings are manufactured from PE100 RC compounds, download compound and technical data sheets below:

BorSafe^TM PE100 RC black HE3490LS-H

BorSafe^TM PE100 RC Orange HE3492LS-H 

BorSafe^TM PE100 RC Un-pigmented HE3493LS-H (brown & green stripes) 

BoreSafe^TM PE100 RC Flexural Modulus

List of manufacturers of PE100 RC compounds – updated Q2 2021

Below is a complete list of approved PE100 RC compounds produced by PE100 Plus manufacturers worldwide.