110mm vs 160mm Underground Drainage Pipes

Choosing the correct underground drainage pipe is one of the most important decisions when you’re designing or installing a drainage system. While 110mm and 160mm underground drainage pipes perform the same basic function, they're designed for different applications and flow requirements.

Understanding Underground Drainage Pipe Sizing 

110mm Underground Drainage Pipe Overview 

110mm underground drainage pipe is the standard choice for most domestic drainage systems. It's commonly used to carry foul water and surface water away from properties, offering an excellent balance between capacity and cost.

For most residential projects, 110mm pipework provides plenty of capacity while remaining straightforward to cut and install. 

160mm Underground Drainage Pipe Overview 

160mm underground drainage pipe is designed for larger drainage systems where greater wastewater volumes need to be accommodated. It's commonly specified for commercial developments, industrial premises, apartment blocks and larger surface water drainage schemes.

Its increased diameter provides additional flow capacity, making it suitable for projects where higher discharge rates are expected. 

The Importance of Pipe Sizing in Projects 

Choosing the right pipe size helps ensure wastewater flows efficiently through the drainage network without increasing the risk of blockages or unnecessary costs. Oversizing can add expense without providing any real benefit, while undersizing may lead to drainage problems as demand increases.

For more guidance, read our article on underground drain pipe sizes.

Key Differences Between 110mm and 160mm Underground Drainage Pipes 

Pipe Capacity and Flow Rates 

The main difference between the two pipe sizes is the amount of wastewater they can carry.  A 160mm pipe has a considerably larger internal capacity than a 110mm pipe, making it more suitable for systems serving multiple buildings or larger commercial sites.

Common Applications 

110mm pipe is typically used on domestic properties and smaller commercial premises. By comparison, 160mm pipe is more commonly found on housing developments, industrial estates, schools, public buildings and larger commercial projects where greater drainage capacity is required.

Installation Requirements 

Although both pipe sizes are installed using similar methods, 160mm pipe is larger and heavier, making handling and installation more demanding. It also requires larger fittings and inspection chambers than a standard 110mm system.

Costs 

Generally, 110mm drainage systems are more economical due to the lower material costs and simpler installation requirements. A 160mm system will usually involve higher costs, but provides the capacity needed for larger developments.

When to Choose 110mm Pipe Sizing 

A 110mm underground drainage pipe is typically the right choice when you're:

• Installing drainage for a single house or bungalow where standard domestic wastewater volumes are expected
• Constructing domestic structures that connect to an existing drainage system
• Installing small commercial drainage systems with relatively low wastewater demand
• Replacing existing 110mm pipework as part of repair or maintenance work
• Looking for a cost-effective drainage solution that complies with the project requirements

When to Choose 160mm Pipe Sizing 

A 160mm underground drainage pipe is generally more appropriate when you're:

• Installing drainage for large commercial or industrial developments
• Serving multiple properties from a shared drainage system
• Managing high wastewater volumes from manufacturing or public buildings
• Constructing larger surface water drainage systems where greater flow capacity is required
• Working to engineering specifications or drainage designs that require increased pipe capacity

Considerations When Choosing A Pipe Size 

Property Types 

The size and use of the building will often determine the appropriate pipe diameter. A single dwelling has very different drainage requirements from a large commercial or industrial property.

Expected Wastewater Volume 

Think about both current and expected wastewater flows. The number of occupants and connected buildings all influence how much capacity the drainage system requires.

Rainwater and Surface Water Requirements 

If the drainage system also carries rainwater or surface water, larger pipe sizes may be required to cope with increased flow during periods of heavy rainfall.

Local Building Regulations 

Drainage systems should always comply with the relevant Building Regulations and any project-specific engineering requirements. Following the approved drainage design helps ensure the correct pipe size is selected from the outset.

Future Expansion 

If a property may be extended or additional buildings connected in the future, it's worth considering whether the drainage system should allow for increased demand rather than only meeting today's requirements.

Get Expert Help From Drainfast 

Whether you're comparing 110 vs 160 underground drainage or simply looking for the right products for your next project, Drainfast can help. We stock a wide range of underground drainage products, including pipes, fittings, inspection chambers and accessories, all available for fast nationwide delivery.

Working on a larger project? Our free material take-off service helps you identify exactly what you'll need before ordering, saving you time and money. To speak with our team, call 01420 555600, email [email protected] or get in touch online.