A ready-to-insert clause for engineers writing a tender or design specification for a geocellular SuDS system in Saudi Arabia. Copy it, adapt the bracketed values to your project, and you have a compliant, performance-based section.
How to use this: the clause below is written in performance terms so it is open and compliant, not single-sourced. Replace the values in [brackets] with your project's design figures (storage volume, load class, infiltration rate). It references the recognised standards — CIRIA C737 for structural design and BS 7533-13 for shallow modular rafts — so any compliant system, including the NGS AquaCell range, can be offered against it.
Last updated: 17 June 2026 · NGS Engineering Team
Geocellular soakaway / attenuation system
1.0 GEOCELLULAR STORMWATER MANAGEMENT SYSTEM
1.1 General
The Contractor shall supply and install a modular geocellular
stormwater management system for [infiltration / attenuation /
combined] of surface water, sized for a storage volume of
[___] m³ and a design storm of [___]-year return period,
in accordance with the project drainage design.
1.2 Standards
The system shall be designed and installed in accordance with
the relevant provisions of CIRIA C737 (structural design of
modular geocellular systems) and, for shallow modular rafts,
BS 7533-13. Where infiltration is proposed, soakaway sizing
shall follow the percolation method of BRE Digest 365, and the
works shall comply with the Saudi Building Code and the
requirements of the relevant municipal authority (MOMAH /
Balady).
1.3 Materials and performance
The geocellular units shall be:
a) manufactured from polypropylene (or equivalent durable
polymer);
b) of not less than 95% void ratio;
c) rated for a vertical load class of not less than [___] kN/m²
appropriate to the [non-trafficked / trafficked / heavy-
duty] loading above;
d) designed for a minimum 50-year service life under buried
conditions;
e) wrapped in an impermeable geomembrane (attenuation) or a
permeable geotextile (infiltration), with welded or
overlapped joints to the manufacturer's details.
1.4 Installation
The system shall be installed strictly in accordance with the
manufacturer's method statement, on a prepared formation, with
bedding, surround and cover materials and compaction as
specified. Inspection and maintenance access shall be provided
to permit CCTV survey and jetting of the installed system.
1.5 Submittals
The Contractor shall submit, for approval: manufacturer's
technical datasheets; structural verification for the design
loading; layout and detail drawings; the installation method
statement; and an inspection and test plan. The supplier shall
hold ISO 9001, ISO 14001 and ISO 45001 management-system
certification.
The clause is deliberately performance-based and open — it specifies what the system must achieve, not a single product, which keeps your tender competitive and compliant. The NGS AquaCell range (Geo-Cellular 30/45/60T and EXO 85/150/200) meets every requirement above; datasheets are on the technical documents page.
Need it tailored to your project?
Send NGS your design data — catchment, design storm, loading and ground conditions — and the engineering team will return a project-specific clause and a sized design. You can also size a soakaway yourself in the NGS Design Studio.
Sources & references: CIRIA C737 (ciria.org); BS 7533-13 (bsigroup.com); BRE Digest 365 (bregroup.com); Saudi Building Code (sbc.gov.sa); MOMAH (momah.gov.sa) / Balady (balady.gov.sa). This clause is provided by NGS as a general drafting aid and does not reproduce any copyrighted standard; the engineer of record is responsible for the final specification and for confirming current municipal requirements.
