When it was decided that The Buchan School would relocate to the King William’s College campus, the design team faced a common choice: demolish and rebuild, or retain and adapt.

Two existing buildings - Jackson House and Stenning - were structurally sound, underused, and well-placed. Rather than clear the slate, the team opted to reuse and reconfigure. A full new-build equivalent would have embodied around 680 tonnes of CO₂e. The refurbishment, by comparison, is estimated at 190 tonnes[1]; an avoidance of 490 tonnes.

That saving comes from materials that weren’t demolished, concrete that wasn’t poured, steel that wasn’t fabricated, and envelope systems that were never required. In everyday terms, it’s equivalent to:

The annual emissions of 105 petrol cars[2]
The carbon captured by 800+ mature trees over 25 years[3]
The energy generated by a 2500 m2 solar PV system over more than a decade[4]

Adaptive Reuse in Practice

The retained fabric included loadbearing masonry, existing slabs, roof trusses, and selected windows and doors. Interventions were targeted and minimal: localised steel insertions, new partitions and linings, updated ceilings, and bespoke joinery to suit new educational layouts.

MEP Design In Support of Reuse

At March Consultants Limited, our role was to ensure that building services supported, rather than disrupted, the logic of reuse. Penetrations were kept minimal, distribution routes were adapted to the existing fabric, and services were carefully coordinated to preserve structural integrity. While many systems are new, they were selected for their compact footprint and high operational efficiency; ensuring their inclusion contributed meaningfully to long-term performance and energy savings.

The project features hybrid ventilation units, each carbon neutral in manufacture[5], across teaching spaces. These units help reduce heat loss by an estimated 47,800 kWh per year, avoiding approximately 10.3 tonnes of CO₂e annually[6]. A further 5,100 kWh/year is saved through CO₂ sensor-controlled demand ventilation, avoiding an additional 2.2 tonnes of CO₂e[7].

These may not be headline-grabbing numbers, but they represent deliberate, cumulative design decisions that enhance the building’s efficiency without compromising its retained structure.

Reuse and Responsibility

While the structural choices drove the bulk of the carbon saving, the MEP design ensured those savings weren’t undermined. In refurbishment, the greatest contribution is often knowing where not to intervene.

Footnotes

Estimates based on lifecycle modelling using RICS WLC methodology and structural engineer’s baseline material schedules.
UK BEIS 2023 emissions factor of 4.66 tonnes CO₂e/year per average petrol car.
Based on an average sequestration rate of 21 kg CO₂/year per mature broadleaf tree (Forestry Commission UK, 2022).
Assuming 250 kWh/m²/year generation for roof-mounted PV in Isle of Man climate.
Manufacturer declaration; embodied carbon offset at point of sale (EPD available).
Based on IOM gas carbon factor of 0.216 kg CO₂e/kWh.
Based on IOM electricity carbon factor of 0.430 kg CO₂e/kWh.

Project Info:

Architect: Wilson Mason Architects

Structural: BB Consulting Engineers

PQS: Bell Burton Associates

Contractor: Excel Group

Client: King William’s College

Ensuring a healthy indoor environment in schools is paramount, particularly given the requirements of BB101 (Guidelines on Ventilation, Thermal Comfort and Indoor Air Quality in Schools). At March Consultants Limited, we believe meeting these guidelines shouldn’t compromise sustainability or occupant health. By adopting hybrid ventilation strategies, educational facilities not only reduce energy consumption but also limit the spread of airborne illnesses—critical in safeguarding both staff and students.

Why BB101 and Good Ventilation Matter

Indoor Air Quality
BB101 mandates minimum fresh-air provision and sets thresholds for parameters like temperature and CO₂. Consistent airflow and effective filtration can also dilute the concentration of airborne pathogens indoors.
Thermal Comfort
Maintaining consistent temperatures helps reduce discomfort and distractions, further supporting a stable learning environment.
Airborne Illness Mitigation
Multiple studies, including those published in The Lancet and The Lancet Respiratory Medicine, have shown that improved ventilation significantly reduces the risk of respiratory infections by lowering the concentration of aerosolised particles. The World Health Organization (WHO) and ASHRAE likewise emphasise ventilation as a key factor in reducing airborne disease transmission.

Ventilation Strategies in Schools

Natural Ventilation
- Benefits: Uses zero fan energy, straightforward when weather conditions are mild.
- Challenges: Significant heat loss in colder months, risk of under-ventilation if users forget to open windows.
Mechanical Ventilation with Heat Recovery (MVHR)
- Benefits: Recovers heat from exhaust air, reducing winter heating loads.
- Challenges: Requires continuous fan energy, potentially raising electricity costs and noise levels.
Hybrid Ventilation
- Benefits: Combines passive (natural) and mechanical approaches; fans kick in only when sensors detect high CO₂ or low temperatures.
- Result: Lower overall energy use than full MVHR, reduced heat losses compared to full natural ventilation, and better indoor air quality—helping mitigate virus transmission by maintaining sufficient fresh air exchange.

How Hybrid Ventilation Outperforms

By blending natural ventilation during mild conditions with selective mechanical assistance in high‑demand periods (e.g. winter mornings, high occupancy), hybrid systems often offer:

Reduced Fan Power: Fans run on-demand rather than continuously.
Moderate Heat Recovery: Recovers a portion of the exhaust air’s heat, cutting winter heating bills.
CO₂ and Pathogen Control: Constant monitoring ensures classroom air remains fresh, diluting airborne microbes.

Such demand-driven ventilation aligns with BB101 thresholds while also adhering to WHO and ASHRAE guidance on maintaining healthy airflows to reduce infection risks. In essence, a well-tuned hybrid solution can significantly lower energy costs and improve occupant health in comparison to standalone natural or fully mechanical strategies.

MCL’s Approach to Healthy, Efficient Schools

At March Consultants Limited, we design and commission hybrid ventilation solutions in both new builds and refurbishments, ensuring they meet BB101 standards. Through meticulous coordination with architects and structural engineers, we integrate:

Demand-Controlled Ventilation: Sensors modulate airflow based on real-time CO₂ and temperature readings, maintaining air quality and mitigating the spread of airborne illnesses.
Efficient Heat Recovery: Systems that balance heat retention with minimal fan run‑times.
Robust Controls: Centralised, user-friendly controls let facility managers monitor and adjust ventilation settings to accommodate changing occupancy levels.

This holistic approach helps schools provide comfortable, healthier, and energy-efficient environments—demonstrating that compliance with BB101 and controlling airborne infections need not inflate utility bills.

Ready to Learn More?

If you’re looking to enhance air quality in your educational facility while keeping energy costs and infection risks in check, reach out to us at March Consultants Limited. Our MEP engineering team can guide you through the nuances of hybrid ventilation, ensuring a well-commissioned system that ticks all the boxes: BB101 compliance, energy efficiency, and occupant wellbeing.

For further insights, follow March on LinkedIn. Let’s collaborate to create modern, resilient spaces where students and staff can thrive safely and sustainably.

Related Projects:

The Buchan School Refurbishment

Henry Bloom Noble Primary School

Ballakermeen High School Post-16 Extension