Standard Manhole and Sump Sizes in Malaysia — What Designers Should Know #

This article summarizes the key standards, common dimensions, and practical recommendations setup based on Malaysian practice.

Circular Manholes — The Only Fully Standardized Category #

Circular precast manholes are governed by MS 881 (Precast Concrete Pipes and Fittings).

They are widely adopted by major manufacturers such as OKA, Hume, and Southern Precast.

Typical internal diameters include:

• 1000 mm
• 1200 mm
• 1350 mm
• 1500 mm
• 1800 mm
• 2100 mm

These dimensions are consistent nationwide and suitable for both sewer and stormwater applications.

Rectangular or Box-Type Manholes — Common but Not Codified #

Rectangular manholes remain non-standardized at the national level. Designers typically refer to JKR Standard Specifications, older MS 1228, or consultant-specific drawings.

Common internal dimensions seen in practice include:

• 600 × 760 mm (for depths ≤ 2 m)
• 900 × 900 mm (for depths > 2 m)
• 1000 × 1000 mm

These serve as de facto standards for inspection chambers and junction boxes, even though no official table exists in any Malaysian Standard.

Sumps and Catchpits — Semi-Standardized by Practice #

Rectangular sump pits are guided by MSMA (2nd Edition) and JKR Drainage Works Specifications, supported by common manufacturer catalogs.

Typical internal dimensions include:

• 450 × 450 × 600 mm
• 600 × 600 × 900 mm
• 900 × 900 × 1200 mm
• 1200 × 1200 × 1200 mm

Depths typically range from 1.0 m to 1.5 m, with sump pits 150–300 mm below outlet level.
Circular sumps are often created by repurposing precast manhole rings of 1050 mm or 1200 mm ID, especially where hydraulic layout favors a circular structure.

Manufacturer Catalog Units — Small Precast Modules #

Smaller sump modules appear in manufacturer catalogs from MS Pipe, CKC Concrete, and LTH Precast.
Common units include 430×430×500 mm, 450×450×600 mm, and 600×600×900 mm, often configurable in depth and cover type.

These are popular for housing or commercial projects with limited space.

Recommended Starting Sizes for Civil 3D / MiTS Catalog Setup #

Conclusion #

• Only circular precast manholes are officially standardized in Malaysia.
• Rectangular manholes and sumps rely on common industry practice rather than MS.
• Manufacturers like OKA, CKC, MS Pipe, and LTH Precast offer flexible dimensions within these typical ranges.