DRAINAGE
Putting the case for vacuum drainage
Kris Wojcik of specialist vacuum drainage and sanitation manufacturer Jets Vacuum AS explains why drainage deserves far more attention in healthcare design, asks who should be responsible for key decisions, and questions whether alternatives to gravity drainage – such as vacuum drainage – could deliver safer outcomes.
The standard for delivery of traditional gravity drainage systems reflects its rich history. Conventional gravity drainage systems rely on vertically aligned soil and waste stacks, with the location of sanitary appliances largely dictated by the position of these stacks. The maximum horizontal distance between appliances and the vertical stack is limited by drainage gradients and hydraulic performance requirements, reducing flexibility in building layouts. Each vertical stack requires multiple penetrations through intermediate floor slabs and the roof, which increases coordination requirements and introduces additional fire-stopping and waterproofing considerations. At ground level, the stacks typically discharge into below- ground drainage networks via inspection chambers or manholes, creating a system of interconnected underground pipework that requires sufficient falls and regular access for maintenance. Rather than repeating the mechanics and standard for
the design of traditional underground drainage, let us move to the heart of the matter: why, in the 21st century, are healthcare buildings still designed and constructed with internal manholes within the building envelope? The New Hospital Programme (NHP) provides the ideal opportunity and vehicle for a complete design reset in every aspect to rethink and imagine a building where each element and design choice provides a best-in-class solution to prevent and mitigate infection spread, by starting to empower the ‘thought process’ before pipes are cast in concrete for the next 100 years. Academic evidence that underground drainage is
providing a superhighway for infection transmission is abundant from multiple attributable sources; on this basis, no pipe route should be designed, let alone installed, if it has not been first rigorously interrogated to confirm why the pipe is required and why it should be placed in that particular location. The merits of each pipe should be considered and what alternative solutions are available explored as part of the design process; this is currently not the process that prevails.
How the downhill journey starts The current regulatory documentary landscape is silent about who owns and sets the project drainage ‘strategy’. Who, then, is empowered to make decisions about the drainage strategy? The client, architect, project director, water safety group, consultant design engineer, or finance director? The consensus is that each of the above plays an important role in assessing risk, with each responsible for a different slice of the overall ‘risk pie’. However, no
single stakeholder takes a holistic view of the complete risk profile. As a result, each specialist tends to satisfy their own specific requirements, effectively ticking their own individual box before moving on to the next priority, often without fully understanding the wider implications, the cumulative impact of design decisions, or the alternative solutions that may better reduce overall risk. Having had access to numerous current healthcare
setting planning applications, you do not need the services of a Large Language Model to understand that the evolution of gravity drainage moves at a truly glacial pace. The largest legacy data source is from buildings we have all grown up around: home, school, university, work, offices, so the next question must be: how similar and relevant are these to healthcare buildings? The answer is: ‘not a lot’. While locating manholes within the building envelope of most buildings is a regular and not particular impactful occurrence, this is totally the converse in healthcare settings where the words writ large are INFECTION CONTROL. So how does a strategy that embraces internal access points which have been identified as a prime source of infection transmission remain a central design aspect for healthcare settings? The typical misconception is that there is no alternative. However, there are at least two valid alternatives:
October 2026 Health Estate Journal 81
The Royal Cornwall Hospital in Truro.
All photos courtesy Tim Pestridge, BAM Construction
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