Exel :: Vitrified clay pipes and fittings

Small Diameter Clay Pipes

Introduction

Approvals

Bedding requirements

Cost benefit

System performance

Warranty

Technical Details for Sleeve Couplers

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Recommended Bedding Requirements

Subsoil Conditions and Bedding Classes

Type of subsoil	Conditions of subsoil	Field test applicable
III Clay Sandy clay	Stiff Stiff	Cannot be moulded with the fingers, and requires a pick or pneumatic or other mechanically-operated spade for its removal
IV Clay Sandy clay	Firm Firm	Can be moulded by substantial pressure with the fingers and can be excavated with graft or spade
V Sand Silty sand Clayey sand	Loose Loose Loose	Can be excavated with a spade. Wooden peg 50mm square in cross-section can be easily driven
VI Silt Clay Sandy clay Silty clay	Soft Soft Soft Soft	Fairly easily moulded in the fingers and readily excavated

Pipe Bedding Materials

Nominal bore of pipe mm	Size of material nn
Nominal bore of pipe mm	Single sized	Graded
100	10	-
150	10 or 14	14 to 5
200	10 or 14	14 to 5
225	10, 14 or 20	10 to 5 or 20 to 5
250	10, 14 or 20	10 to 5 or 20 to 5
300	10, 14 or 20	10 to 5 or 20 to 5

Class D (Bedding factor 1.1)

If the sub-soil falls within types 111 to V1 in Table E1 in Approved Document A1/2 of The Building Regulations 1992, the relevant part of which is reproduced above, hand-trim the trench bottom with a spade to support the pipe along the length of its base, allowing for any socket recesses.

Class N (Bedding factor 1.1)

Where the subsoil cannot be trimmed accurately, excavate the trench to a depth of at least 50mm below the pipe barrel for SuperSleve/EuroTop, increasing this in rocky ground to 150mm. Form a bed for the pipe from as-dug if suitable, or granular material, well compacted and covering the full trench width. BS 8301:1985, Section 11 gives details of materials suitability. The pipe barrel should be rested firmly on its bedding. Any granular material used should be packed by slicing with a spade.

Class F (Bedding factor 1.9)

Recommended for maximum installed cost savings.

Class B (Bedding factor 2.5), Class S (Bedding factor 2.5)

The bedding factors listed above are limited to use with clay pipes only. This provides the benefit of savings in excavation, removal from site and imported material, especially when compared with flexible pipes which require a full granular surround.

Recommended Bedding Requirements

At shallow depths, the depth of cover used for design purposes should be that which will apply during site construction. This may be less than the finished level. The minimum depths of cover are 1.2m under roads and 0.6 in fields and gardens. Where pips must be laid at depths less than this, precautions must be must be taken to reduce the risk of damage.

	Main Roads Full loads (soil):2000 Kg/m2 Vehicle loads: 8 wheels 112.5 kN each including impact factor

	Gardens and Fields Full loads (soil):2000 Kg/m2 Vehicle loads: 2 wheels 30 kN each impact factor 2.0

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