27 November 2020
Designing Effective Plant Rooms
Plant rooms may call to mind the concept of greenhouses, but they are far less pretty in the MEP (mechanical, electrical, plumbing) landscape. Dedicated to housing mechanical equipment and related electrical equipment, a plant room, or mechanical room or boiler room, will not see human occupancy or be used for storage. It is a building’s nerve centre and contains the equipment required to supply ventilation, electrical distribution, water and other building services. Being such a critical part of the building, it is vital that precise MEP services, or M&E design services, are involved in its design.
The contents of a plant room will typically consist of:
- Switch gear
- Elevator machinery
- Air handling units
- Chillers, refrigeration units
- Ducts, filters
- Water heaters and tanks
- Boilers, thermostats
- Main distribution piping and valves
- Heat exchangers
- Sprinkler distribution piping and pumps
- Gas pipework
- Electrical equipment and control panels
- Back-up electrical generators, compressors
- Specialist equipment for swimming pools, laboratories, factories, etc.
- Water pumps (for domestic, heating/cooling, and firefighting water)
- Other HVAC (heating, ventilation and air-conditioning) equipment
What are the considerations for an effective plant room?
Well, here is where size really does matter. The size and type of building determines its plant room’s size. It’s even possible for large buildings to have multiple plant rooms. Sometimes, plant rooms can take up space on an entire floor or more than one floor. Different plant rooms may also have different functions, e.g. battery, transformer or boiler rooms, etc.
In the case of plant room design, the priority is functionality, not aesthetics. So, understanding the functioning of a mechanical system is paramount before designing begins.
Of its several functions, one task a plant room performs is the management of exhaust gases. Combined heat and power (CHP) plant rooms are placed either in the basement or on top of the roof of a building, ensuring it sits on a sturdy mounting platform. Similar to boilers, the required volumetric flow rates of ambient air are drawn in from outside air for the combustion and ventilation of the plant room. An exhaust system directs the combustion products away from the building’s ventilation system through an outlet point, so that it does not accidentally re-circulate in the building. Many times, the exhaust duct outlets extend to a building’s roof, taking into account duct material that is compatible, insulation and vibration isolation.
Designing a plant room takes this and many other factors into consideration. To design an optimal mechanical system in a plant room, consider the following:
- Place the plant room adjacent to the garage (in a house). Rooms situated over a garage will have longer heat runs. Hence, they should ideally be close to the furnace.
- A furnace should be located along a beam whenever possible, to allow duct lines to be bulk headed in with the beam.
- Plant rooms or mechanical rooms should be situated near the exterior side yard.
- Ductwork sizing must be checked, and since ductwork runs in the opposite direction of floor joists, it must be drawn in such a direction as much as possible. Typically, a bulkhead is 40, 48, or 56 inches wide, depending on the square footage of the building.
- If an HRV (heat recovery ventilator) is included, plant rooms will need to be bigger. An HRV makes air healthier and cleaner by constantly replacing stale air with fresh outdoor air. They are also known as air-to-air heat exchangers, as they use exhaust air to preheat or cool incoming air.
- Must have easy access for maintenance staff
- Must have room to expand if required
Plant room designers also need to think about the following requirements:
- Placement on the site should be so that those performing maintenance/replacement of equipment should have easy access routes.
- Locations should be determined with an eye on potential future expansion.
Room & Space Planning
- 800mm to 1m circulation width should be maintained throughout the plant room
- Circulation zones should accommodate different sizes and types of equipment and replacement parts.
- A minimum of 20% additional space should be allowed for on boards and in cabinets for future additional equipment.
- Plant equipment must have appropriate protection.
- Service technicians must have appropriate amenities.
Materials & Finishes
- Generally, louvred facades are used for shading outside plant rooms.
- Lightweight roofs are preferred.
- Preference for louvred or naturally ventilated façades
- When placed externally, use screening devices
- Should be impact resistant
- Should be durable to withstand minor impacts with tools and equipment
- Low maintenance, spill-resistant and slip-resistant finish.
- Can be unfinished concrete
- Non-combustible ceiling linings are mandatory
- Glazing is not required.
- Privacy is important, as equipment should be concealed from public view
- For external plant rooms, louvred doors are recommended.
- Fire rated/acoustic doors compliant to local standards
- Steel or aluminium framed with a lock
- Security type/group for maintenance access only
- Acoustic attenuation when close to teaching or office spaces
- Sound transmission to adjoining spaces must be minimised.
- Constant natural ventilation is preferred.
- Natural/passive supply of air
- Exhaust is required, as equipment generates heat
- Potable cold water is needed for hose connections.
- Sanitary drainage is required.
- Drain for taps with hose connections
- Minimum 150 lux is required
- Lights should turn off automatically after 1 hour, with a manual override.
- Minimum two data ports are needed, one for equipment monitoring and one as a test point.
Though unobtrusive and discreetly tucked away from disturbing the view, planning for plant rooms are an integral part of building design, requiring the diverse, technical talents of MEP engineers or consultants. As Building Information Modelling (BIM) slowly eased its way into design modelling, plant room design also benefitted from its many advantages, and MEP designers were compelled to learn how to use BIM to best suit their requirements.
Increasingly, MEP designers in India are being sought after for their experience and expertise in providing accurate BIM coordination services. With the right BIM service providers, designing effective plant rooms need no longer be challenging, costly or time consuming.
XS CAD has valuable experience as a BIM service provider, delivering BIM MEP services for MEP engineers, M&E design consultants, contractors and fabricators. Our range of services for structural, architectural and building engineering firms, such as building services design consultants and contractors across the world, include BIM coordination services, mechanical drafting services, and mechanical engineering design services. We provide these M&E design services by using Revit, AutoCAD, Navisworks, and BIM 360 Design for cloud collaboration.