CIBSE recently hosted the official launch of TM70: 2025 – Tall Buildings Drainage Design, a landmark publication that establishes a new benchmark in performance-based drainage design for tall buildings. The event brought together engineers, academics and industry professionals to celebrate this significant advancement in building services engineering.
Developed through a collaborative effort between members of the SoPHE Technical Committee, academic researchers, professional engineers, and industry partners, TM70 translates full-scale experimental testing and validated transient-flow simulations into practical guidance for real-world application.
The launch featured insightful presentations from the authors, including Professor Michael Gormley of Heriot-Watt University and Jassim Daureeawo, SoPHE Technical Chair. Attendees had the opportunity to engage with the experts, ask questions and explore how the guide can be applied across a variety of tall building projects. The presentations were followed by a lively networking reception, allowing participants to exchange ideas and build connections across the sector.
About TM70: Tall Building Drainage Design
Effective drainage systems are essential for safely removing human and domestic waste, protecting public health, and preventing the spread of pathogens. While most existing design codes focus on low- to medium-rise buildings, tall buildings present unique challenges that often lie outside standard guidelines.
CIBSE’s TM70 addresses these challenges by offering a robust, evidence-based framework for designing drainage systems in tall buildings. The guide covers:
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Accurate flow rate estimation: Methods for calculating water flow rates and determining pipe sizes and storage capacities for optimal performance.
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Global standards integration: Guidance aligned with major international standards, including BS EN 12056, DIN 1986-100, IPC/UPC, AS/NZS 3500.2, SHASE-S 206, GB 50015, and regional resources such as the ASPE Plumbing Engineering Design Handbook.
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Advanced modelling with AIRNET: Simulations of air and water flows and pressure dynamics, validated for safer, more reliable drainage.
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Risk-based design for tall buildings: Strategies to address height-related performance issues through enhanced ventilation and optimised system design.
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Practical design guidance: Advice on pipe sizing, system configuration, pressure equalisation, and managing offsets.
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Performance testing tools: Robust commissioning tests to verify designs operate as intended and to diagnose existing systems.
The guide combines laboratory research, full-scale testing, and advanced numerical modelling, providing designers with the tools to create resilient, high-performing drainage systems for tall buildings.
The TM70 launch was widely regarded as a success, with attendees praising the clarity, technical rigour and practical applicability of the new guidance. CIBSE looks forward to seeing how the publication shapes the design of safer, more efficient tall building drainage systems around the world.