Erik Mul at ACO Building Drainage looks at the drainage issues that arise when high-use washrooms have limited space for installation, and how to solve them.
In gyms, spas and hotels, drainage has to fit around a lot besides the finished floor. A shallow floor build-up, restricted service voids or existing pipework can all make the job more difficult. There are demanding hygiene standards and sustainability targets to hit, while still being expected to deliver a finished space that looks the part.
Much of the drainage will be out of sight once the work is complete. That can make it easy to overlook during design. It is only when something goes wrong that its importance tends to become obvious; poor flow, blockages and unpleasant odours can all affect the way a washroom performs, and putting problems right afterwards can be expensive.
A further reason to get it right early is that in high-end hospitality, the end user experience matters hugely, so drainage problems can affect the business as well as satisfaction with the finished job. Considering the drainage at the outset gives the design more opportunity to work with the restrictions of the building instead of trying to accommodate them later.
Working within existing constraints
Refurbishments and retrofits can leave very little room for manoeuvre as floor build-ups may be low, service voids restricted and existing pipework can make routing more complicated. These are not reasons to accept poor drainage. Effective drainage should remain ‘non-negotiable,’ even where conditions make it harder to achieve. Good drainage is more achievable when architects have a strong understanding of the available options – be they solutions or approaches. The aesthetic requirements of a washroom need to be enabled by the drainage in place, rather than one of these aspects having to compromise so the other can be kept to a high standard.
The hydraulic demands can also change considerably in places such as gyms and hotels where levels of use fluctuate, significantly increasing the risk of pooling. That makes the way the system will perform under peak demand an important factor to be accounted for during design.
Making the installation adaptable
When space is tight, adaptability becomes more useful and low-profile systems can help where floor build-ups are limited. Flexible outlet configurations and modular components can reduce the need for extensive structural alterations.
There can be value in having some adjustment within the installation too, such as adjustable frames and different outlet orientations, which can make it easier to work with existing substrates and waterproofing systems.
For architects, this means looking beyond whether a drainage system will fit ‘on paper.’ The conditions for a refurbishment or retrofit are rarely the same from one project to another, so having some scope to adjust the installation can make a big difference.
Checking hydraulic performance
The starting point is the expected peak level of use. Channels and gullies need to have suitable flow rates for those conditions to help reduce the risk of standing water and ensure the drainage system can deal with periods of high demand.
Trap design and channel capacity also need to be considered, though neither should be viewed separately from the rest of the arrangement.
A component can perform as expected in isolation without necessarily giving an accurate picture of the complete drainage system. The channels, gullies, traps and other elements need to be considered as part of the same installation when assessing how it will perform.
Keeping maintenance practical
A washroom that sees high usage every day needs drainage that can be cleaned without unnecessary difficulty, so maintenance is another consideration for the specification stage.
Access is important here, particularly where routine cleaning needs to be carried out without specialist tools. The way debris is dealt with is worth planning for too; a design that limits build-up and makes routine cleaning straightforward can help operators maintain high hygiene standards without adding needless work to the maintenance schedule.
These practical points are easy to miss when the drainage will eventually be hidden beneath the finished washroom.
Bringing the requirements together
In a hotel, gym or other high-use commercial washroom, hydraulic performance is only part of the picture. The drainage also has to fit the available space, remain manageable to maintain, and support the aesthetic appearance of the finished room.
The broader point for architects is that these requirements do not need to be dealt with separately. Drainage can be considered alongside the rest of the washroom design from an early stage, when there is still scope to take account of floor build-up, existing conditions, hydraulic demand, maintenance and aesthetics.
Leaving it until later can mean working around decisions that have already been made. Considering it earlier gives the drainage a better chance of fitting the project, rather than the project having to fit around the drainage.
Erik Mul is technical product manager at ACO Building Drainage