Trial / Demo
IES conducted complex CFD analysis to validate the internal airflow requirements for Glasgow’s Safe Drug Consumption Rooms. This challenging project had to prove effective air containment and pressure differentials, while meeting stringent regulatory standards.
IES was commissioned by Hawthorne Boyle to study the airflow patterns for the UK’s first and only Safe Drug Consumption Rooms. The Thistle Centre in Glasgow, which opened in January 2025, is owned by Glasgow City Council and operated by the NHS.
Hawthorne Boyle has 40 years’ experience in the specification, design, construction and management of building services engineering. They approached IES in early 2024 after completing the mechanical design of the building. IES’ remit was to conduct a detailed CFD (Computational Fluid Dynamics) analysis, following initial site visits and extensive consultations with the NHS to understand the compliance requirements.
IES’ expert CFD services consider airflow at the microscopic level, helping to test and optimise designs to achieve better performance levels in terms of comfort, health and safety, energy and costs. Hawthorne Boyle needed IES to virtually prove that the building design was meeting strict standards in terms of predicted airflow and pressure differentials.
The building was a refurbishment project, which meant there were unique design complexities, including spatial constraints, such as low ceiling void depths. Furthermore, the booths were designed with open fronts for constant monitoring of occupants, which posed a significant challenge for air containment without physical barriers like doors.
The facility’s room types, some situated next to each other, all have distinct air pressure requirements. The main challenge was maintaining negative pressure within the injection booths to prevent the dispersion of airborne substances elsewhere, whereas the treatment rooms needed a neutral balance. Irregular occupancy patterns across the eight booths necessitated a comprehensive range of simulation scenarios, with complex algorithms to calculate various combinations of booth occupancy.
The design had to meet the SHTM (Scottish Health Technical Memorandum) standards for airflow and ventilation, as laid out by the NHS. A primary design parameter within this SHTM guidance was meeting the leakage requirements for both negative and positive pressures, particularly with some booths close to the fresh air supply.
CFD offers granular insights into localised conditions at a specific moment. A critical aspect of the analysis was proving that the negative pressure in the open-fronted injection booths effectively contained any airborne substances within the occupant's immediate area, preventing leakage into open areas or adjacent rooms. This was achieved through the strategic placement and design of extract grilles. The design also had to meet anti-ligature requirements in certain areas which would have an impact on the positioning of the grilles for the injection booths.
IES’ CFD simulations accounted for every physical element of the existing building’s geometry, including all furniture, fixtures and even door recesses. Everything had to be meticulously modelled to create an accurate virtual representation of the existing facility, which significantly increased the computational complexity.
“This was a very interesting project and the CFD analysis confirmed that the pressure differentials between the various zones met SHTM standards. IES has completed similar studies for hospital rooms, for example, designing effective air curtains for multiple use operating theatres. IES specialises in making sure airflow is accurately analysed and proving it can be kept distinct to prevent cross-contamination."
- Harshad Joshi, CFD Consultancy Manager, IES
The CFD analysis conducted by IES provided robust, visually compelling and highly accurate data that confirmed the ventilation system design met all specified criteria and regulatory standards. The analysis conclusively demonstrated that the negative pressurisation in the open-fronted injection booths effectively contained airborne substances, preventing their dispersion into other areas of the facility.
IES's work proved that the building's ventilation system, including the complex pressure differentials between disparate zones, fully complied with the stringent Scottish Health Technical Memorandum standards.
“The successful operation of the facility confirms the precision of IES' CFD analysis, demonstrating that the system could not only function effectively at design stage, but continue to perform as intended today. The CFD analysis provided compelling evidence of the design's efficacy. This project was my first collaboration with IES, and I would eagerly welcome the opportunity to partner with IES again in the future.”
- Paul Singleton, Mechanical Engineer, Hawthorne Boyle
With over 300 years of combined experience, IES Consulting has unmatched expertise in the area of virtual building analysis. They have performed over 350 CFD simulation projects globally, encompassing both internal and external studies, to help clients test and optimise their designs in detail and achieve superior performance outcomes. For more information, explore our CFD services.
Engineers looking to take the first step into early stage CFD simulations can also check out IES’ MicroFlo-CFD airflow simulation software.
