For hundreds of years most of the world’s toilets have operated on 110mm pipes. They are bulky and rely on regular flushes, with large volumes of water, to maintain the correct function and stay blockage and odour free. The operation and installation of such toilets demand heavy infrastructure, presents limitations and has a negative impact on water and energy consumption.
Propelair’s use of a 50 mm waste pipe, combined with low water use toilet technology, transforms traditional plumbing constraints into flexible, cost-effective, and space-efficient solutions. This enables architects, engineers, and facility managers to unlock new possibilities in both new builds and refurbishments, while delivering measurable commercial bathroom water conservation and commercial washroom cost savings.
Why Installation Flexibility Matters More Than Ever
The way we design, build and operate buildings has changed dramatically, driven by the need to reduce carbon, optimise resources and meet ESG targets. From stricter building codes to smart technologies that manage heating, lighting and water, the industry has embraced more efficient, data-led solutions. Materials and construction methods have also evolved, reducing emissions, limiting harmful substances like VOCs and prioritising local, sustainable sourcing.
At the same time, facility management is shifting toward intelligent asset management, using data and connected technologies to replace reactive maintenance with proactive, cost-efficient operations. This is reshaping how value is measured, moving beyond upfront cost to whole-life performance and ESG impact.
Frameworks like BREEAM and LEED have helped set new standards for sustainable buildings, yet public washrooms remain a major gap, despite being one of the largest drivers of water use in commercial spaces. As buildings are increasingly refurbished and repurposed, particularly across the UK and Europe, there is growing demand for flexible, high-performance washroom solutions that support both environmental goals and modern design constraints.
This is where Propelair sets washrooms apart
The 50 mm waste pipe is one of the most practical and often overlooked advantages of the Propelair system. Unlike traditional gravity-fed systems that rely on large 110 mm pipes, Propelair’s design enables a fundamentally different approach to plumbing. It reduces installation complexity, unlocks design freedom, and creates opportunities in spaces that were previously considered unworkable. For facility managers, architects, and developers, this means more than just installing water saving or low flush toilets. It means rethinking what is possible within a washroom environment.
Key Areas of Installation Flexibility
- Less structural work and lower cost
- More design flexibility for architects
- Meeting ESG requirements – LEED and BREEAM
- Space saving and layout optimisation
- Enables installations where traditional systems can’t
- Supports faster, simpler installs.
1. Less Structural Work and Lower Cost
Traditional toilet systems rely on large 110 mm soil pipes, which require significant structural intervention. Core drilling, slab penetration, and extensive pipe routing can quickly increase both cost and project timelines. By contrast, Propelair’s 50 mm waste pipe significantly reduces the scale of these requirements. Smaller pipe diameters mean:
- Less invasive installation
- Reduced labour and time on site
- Lower overall project cost, particularly in retrofit environments
For projects involving commercial water efficient toilets or upgrading to high efficiency toilets for commercial washrooms, this difference becomes highly impactful. Refitting older buildings, where structural limitations are often a barrier, becomes far more viable. From a financial perspective, reducing installation complexity directly contributes to commercial washroom cost savings, not just during installation, but across the lifecycle of the building. In traditional construction, coring for a 50 mm pipe is also faster, cleaner and far less invasive than cutting for a standard 110 mm drainage pipe, making it a key advantage when penetrating floors or working within structural slabs.
This is especially relevant in modern builds that are delivered partially completed or using SIPs (Structurally Insulated Panels), where cutting or drilling for services can compromise structural integrity. Because these panels are factory-bonded for strength and thermal performance, any modification must be carefully controlled. Using smaller-diameter pipework reduces the need for large cut-outs, minimises structural impact, and speeds up installation and sealing. It also allows pipework to run within cavity walls, stud systems or tight voids, supporting faster construction, easier retrofits and more efficient modular building design.
Top tip for facility managers: When evaluating low flush toilets, don’t just compare unit costs. Include installation complexity and structural work in your ROI calculation, it often changes the business case significantly.
2. More Design Flexibility for Architects
One of the biggest constraints in washroom design is pipe routing. Large diameter pipes limit where toilets can be placed and how layouts can be configured. The smaller 50 mm pipe changes this completely. Because it can be routed more easily through walls, floors, and ceilings (where building codes allow), it allows:
- Greater freedom in washroom layout
- Easier navigation around structural constraints
- More creative and efficient use of space
This is particularly valuable when designing sustainable washroom solutions in buildings with limited or irregular layouts. Architects can prioritise user experience, accessibility, and efficiency, rather than designing around plumbing restrictions.
For modern developments aiming to integrate eco-friendly toilets and smart water saving toilets, this flexibility is essential.
In more detail, traditional gravity drainage relies on a consistent fall of around 2.5–4°, without it, pipes are prone to blockages due to poor waste carry. Gravity or Symphonic Low-flush toilets often exacerbate this issue as the reduced water volume lacks the lubrication and momentum to allow waste to move effectively down a traditional 110mm float, limiting how far fixtures can be placed from the soil stack and forcing straight-line layouts or making installations prone to blockage.
By contrast, Propelair’s pressure-assisted system actively drives waste through a 50 mm pipe, enabling longer runs, bends and shallower falls offering far greater layout flexibility to designers. This is especially valuable in refits and high-density buildings, where additional or accessible washrooms must be installed within tight structural constraints.
Top tip for facility managers: Engage your plumbing and design teams early when considering water efficient sanitation solutions. The flexibility of smaller pipework can unlock layout improvements that enhance both user flow and operational efficiency.
3. Meeting legislative requirements – LEED and BREAAM
BREEAM and LEED certifications have had a growing influence on how buildings are designed, measured and operated for the last 25 years. The use of Propelair pressure assist toilets in projects directly aligns with both frameworks through measurable water, energy savings and operational efficiencies.
Its industry-leading 1.35 litre flush delivers up to 85% water savings compared to conventional systems, contributing valuable credits toward overall ratings while also unlocking innovation points through compatibility with treated grey water sources, including HVAC recovery systems.
Beyond water reduction, the lower volume used significantly decreases the energy required for water treatment, heating and distribution, strengthening ESG performance across both new builds and retrofits. From a performance perspective, Propelair consistently achieves MAP 1000g flush standards, even in high-traffic environments, outperforming many traditional 6 litre and low-flush systems that often compromise flush quality, appearance and hygiene. The rimless pan design, combined with antimicrobial components, reduces cleaning time, chemical usage and long-term operational costs, supporting both sustainability targets and reducing total cost of ownership.
In addition, the system’s use of smaller diameter pipework can simplify installation, improve material handling on-site and accelerates project timelines. Together, these factors make Propelair a powerful contributor to sustainable building strategies, particularly where flexibility, performance and ESG outcomes must align.
4. Space Saving and Layout Optimisation
Space is one of the most valuable assets in any commercial building. Traditional plumbing systems on 110 pipes often consume more space than necessary, limiting layout possibilities and capacity. With a 50 mm pressure assisted system, the constraint of bulky pipework is reduced, enabling:
- Unlocking usable floor area that was previously “out of reach”.
- The possibility to add more cubicles within the same footprint washrooms
- Better utilisation of high-value commercial space
- No need for additional pumps or central services
For high-traffic environments such as retail centres, offices, and transport hubs, this can have a direct impact on both user experience and revenue generation. When combined with commercial toilet water savings delivered by the Propelair OneThreeFive toilet, the result is a dual benefit, saving both water and improving space utilisation. This is especially relevant for organisations seeking the best water saving toilets for businesses, where efficiency must extend beyond water usage alone.
Top tip for facility managers: Review underutilised washroom layouts. By switching to low water use toilet technology, you may be able to increase capacity without expanding the physical footprint.
5. Enables Installations Where Traditional Systems Can’t
Conventional gravity-fed toilets depend on large pipes and consistent fall gradients. This limits where they can be installed and often excludes challenging environments. Propelair’s system removes these limitations as it can:
- Run horizontally over longer distances
- Use flexible sanitary hoses
- Be installed in complex retrofit scenarios
Designers’ office space allocation, per desk, has been reduced significantly during the past 50 years. Accessibility requirements and working styles have also changed. Refits of commercial properties from the 1980’s and 1990’s may require additional toilets to be provided in areas that are not ideally positioned to connect to legacy soil stacks. Propelair’s pressure assist 50mm pipe connection can accommodate shallow to zero falls, and long runs, without the need for additional pumps or expensive new soil stacks to be added and routed through narrow voids or existing service ducts. This enables new possibilities for the location of toilets and washrooms in high performance sustainable buildings.
Propelair’s ability to deliver high quality sanitation in non-conventional environments, including marine or off-grid/remote locations is highlighted in the case study: https://propelair.com/case-study/propelair-is-ideal-for-off-grid-sites/
This shows how tech enabled low flush pressure assisted toilets can deliver reliable performance even in remote locations, enabling high quality sanitation for water-stressed regions and off-grid locations by reducing the cost and carbon impact of delivered water and the cost of waste from septic tanks.
Top tip for facility managers: If you have areas in your building that have been ruled out for washrooms due to plumbing constraints, revisit them. Modern water efficient pressure assist solutions may make them viable.
6. Supports Faster, Simpler Installs and fleet Management.
Time is a critical factor in any commercial project. Extended installation periods can disrupt operations, increase costs, and impact tenant or customer experience. The use of smaller, lighter 50 mm pipework, together with Propelair’s ability to operate without separate pumps or vacuum systems in service rooms or ceiling voids, significantly simplifies installation. This delivers:
- Faster installation timelines
- Less disruption in occupied buildings
- Reduced reliance on heavy civil works
For facility managers overseeing upgrades to IoT connected toilets or high efficiency toilets for commercial washrooms, this means projects can be completed more efficiently and with minimal operational impact. In sectors such as healthcare, education, and retail, where downtime is not an option, this benefit becomes particularly valuable. The ability to remotely monitor these assets and track their status enables facility managers to oversee estates more efficiently, coordinate repairs and maintenance proactively, and reduce the need for staff to physically inspect hundreds of locations across a site.
Top tip for facility managers: Plan upgrades in phases using smart water saving toilets to minimise disruption. Faster installs mean you can modernise your estate without shutting down critical facilities.
Final thoughts
The 50 mm pipe does more than reduce the size of plumbing infrastructure. It fundamentally redefines what is possible in washroom design. It transforms a traditionally heavy and rigid system into something flexible, efficient, and future-ready. For facility managers, it means unlocking new opportunities for commercial washroom cost savings and operational efficiency. For architects, it enables better, more creative design. For organisations, it delivers scalable water efficient sanitation solutions that support long-term sustainability goals. In a world where water is becoming increasingly constrained, flexibility is no longer a luxury, it is a necessity.
By: Dr. Neil Keegan, Operations Director, Propelair / Zea Gove, Global Brand Strategist and Marketing Manager, Propelair