Construction Specification & Method

Book One · for the specifier

The Specification

A complete CSI three-part section. Copy it into the project manual, make the bracketed choices, fill the blanks from the design and issue it.

• Part 1, General. Scope, references, definitions, performance requirements, submittals, quality assurance, sequencing, warranty.
• Part 2, Products. Chambers, grommets, liner and accessories, geotextile, pipework, vaults, reservoir, pumps and controls, sand, bridging aggregate, amendments, vegetation, source quality control.
• Part 3, Execution. Subgrade to commissioning, with the nine hold points listed together.

Book Two · for the site team

The Method Statement

Eleven stages, each with what is being done, what it must look like when it is right, and what goes wrong.

1. Set out and strip
2. Cut, fill and compact the subgrade
3. Prove the subgrade
4. Lay the geotextile and the liner
5. Seam, wall and penetrate
6. Set the headers and the vaults
7. Lay and connect the chambers
8. Place the bridging aggregate
9. Import and place the sand
10. Amend, settle and fine grade
11. Charge, prove and plant

Special conditions: benched and sloped construction, trees inside the cell, stopping and restarting work, and the seven things that go wrong.

Book Three · for the resident engineer

Records

Ten forms that between them cover every submittal and hold point Book One asks for.

1. APre-installation checklist
2. BMaterial approval register
3. CSubgrade survey and compaction
4. DLiner seam and penetration log
5. EChamber layout and connection
6. FAggregate depth verification
7. GHold-point inspection and sign-off
8. HCommissioning and charge record
9. IHandover checklist
10. JQuantities basis per 1,000 m²