Round Pipe vs Box Culvert: Which Suits Your Drainage Work?

Last updated: 1 Nov 2026 | 156 Views |

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In short: If the flow is modest and there is enough burial depth, a round pipe is usually the more economical and easier-to-install choice. If you need to carry a large volume of water, burial depth is limited, or you need a wide opening to pass under a road or canal, a Box Culvert is the better fit. The actual size and class should be specified by the design engineer based on the flow and the load on top.

Large precast box culvert being lifted by crane

Round pipe vs Box Culvert

Item	Round pipe (tongue-and-groove)	Box Culvert
Standard	TIS 128-2560	TIS 1164-2559, TIS 1165-2559, TIS 1166-2559 and DOH 2015 design
Sizes made by CCP	Diameter 0.30–2.50 m, length 1–3 m	Width 0.50–3.60 m, length 1–3 m
Class / type	Reinforced, classes 1–4, and non-reinforced	Under-footpath type and under-carriageway type
Cross-section	Circular; resists surrounding soil pressure well	Rectangular; larger waterway area for the same height
Burial depth	Needs soil cover according to pipe size	Suits locations with limited depth, giving a wide opening without much height
Installation	Light units joined by tongue-and-groove; quick to install	Heavy units; needs a crane and a levelled bed
Typical uses	Roadside drains, housing estates, factories, small culverts	Road culverts, main drainage lines, underground canals, highway works
Certification	Made in Thailand (MiT)	Made in Thailand (MiT)

When to choose a round pipe

Moderate flow, using pipe sizes no larger than those commonly available
Enough depth for the soil cover in the design
You want fast installation with little machinery
Works directly with standard manholes

When to choose a Box Culvert

A large volume of water must be carried, such as a project's main drainage line or a road culvert
Limited depth from road surface to pipe invert
You need a wide opening for cleaning or for people to enter for inspection
The job specifies the DOH 2015 design

4 questions before you choose

How much water must be drained? — This sets the cross-section size.
What passes over the top? — Pedestrians or trucks; this determines the class or the under-carriageway type.
How deep can you dig? — If depth is limited, a Box Culvert usually has the advantage.
Can a crane get onto the site? — Large Box Culverts need a crane.

FAQ

Can round pipes and Box Culverts be used together in one system?
Yes, by connecting them through a manhole designed with openings for both types. CCP offers manholes for Box Culverts (Box out) and manholes to the DOH design.

What is the difference between the under-footpath and under-carriageway Box Culverts?
The under-carriageway type is designed to carry heavier vehicle loads. Drawings for both types are on the product page.

Where can I get drawings?
Download them at the bottom of the product page. For sizes without a file, ask our sales team.

Enquiries and quotations: tel. +66 61 409 8877 · LINE @ccp-concrete

Products: Tongue-and-groove pipe TIS 128 · Box Culvert · Manhole for Box Culvert (Box out) · Manhole to DOH 2015 design

Source for sizes/standards: CCP product pages 9339 and 9404 (1 Nov 2026)

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