Planning a laboratory building or refurbishment: the decisions that are expensive to reverse after handover

By Vvon Engineering Team | Published 2026-05-27 | Updated 2026-09-13

Bench layout, services routing, floor loading and storage decided in the right order, plus the commissioning tests worth holding retention against, for anyone building or refitting a laboratory block in Bangladesh.

Scientific & laboratory RFQ checklist (TXT)

Plan equipment access and utilities before freezing a laboratory refurbishment. A rig’s packed dimensions, electrical supply or exhaust route can change the building brief, and resolving those interfaces on drawings is usually easier than after construction.

Laboratory buildings are unusual because the fit-out drives the structure rather than the other way round. What follows is the order in which decisions should be taken, and which of them become permanent once the contractor leaves site.

Write the equipment list before the architect draws anything

The single most valuable document in a laboratory project is a schedule of every item that will ever stand in the room, with its footprint, weight, services requirement and access route. It does not have to be a purchase decision. It has to be an honest expectation, including the equipment you hope to buy in five years.

Give the design team, for each item: length, width and height; operating weight including contained water or product; electrical supply, phases and connected load; water supply and drain requirement; gas requirement; extraction requirement; heat rejected into the room; noise; and whether it must sit against a wall, a window or a door. State the crated dimensions and weight too, because that governs the access route, not the installed size.

Departments resist this because it feels premature. It is not. An architect designing a laboratory without an equipment schedule will produce a well-proportioned classroom with sinks.

Bench layout and circulation

Layout is where teaching quality and safety are decided, and where a small change on the drawing has a very large effect on how the room works.

• Provide code-compliant escape routes. A qualified building and fire-safety designer should determine exit number, separation, travel distance and door arrangement from occupancy and hazards. Keep working positions and stored items clear of escape routes.
• No dead ends between benches. A peninsula arrangement where a student can be trapped at the closed end is a poor design even when the aisle is generously wide.
• Aisles wide enough for two people to pass while one is carrying something, and wide enough for a trolley to reach every rig position. The trolley test is a good practical check on any drawing.
• Sight lines for a single technician. One person should be able to stand at the door and see every working position. Tall storage in the middle of a room defeats this.
• Doors that open in the direction of escape, with vision panels, and wide enough for the largest item that will ever be moved through them, including an access route for future equipment. A laboratory on the third floor with a lift that cannot take a crated pilot plant has permanently limited what it can teach.
• Somewhere to write. Every laboratory needs dry surfaces away from the wet or hot zone where students can record results and open a laptop. Layouts that fill the room with rigs produce soaked lab sheets and results copied later from memory.

On accessibility: level thresholds, at least one bench position at seated working height, and clear turning space are straightforward at design stage and close to impossible afterwards. Include them.

Services: what to get right at first fix

Service	Get this right at design	What it costs to change later
Electrical distribution	Dedicated board with spare ways, per-bench isolators, three-phase to named positions, containment sized with spare capacity	High. Surface trunking, trailing leads and a board with no spare way, permanently
Earthing	Compliant protective earthing and equipotential bonding, with instrument EMC requirements coordinated by the electrical designer	Very high. Retrofitting an earth into a finished building is disruptive and often compromised
Water supply	Supply capacity and quality matched to equipment, with appropriate isolation and approved backflow protection	Moderate for a branch, high for a new riser
Drainage	Chemically compatible collection and drainage, with segregation and treatment for the actual waste; dilution is not a substitute for compliance	Very high. Falls are set in the screed and cannot be adjusted
Gas	Cylinder store outside with ventilation and restraint, reticulated lines with isolation at the point of use, fixed detection	High. Cylinders end up inside the laboratory, which is the arrangement everybody regrets
Extraction	Riser space and duct routes reserved, discharge above the roofline away from intakes, make-up air path, fan position and mounting	Very high. A duct route not reserved at design cannot usually be created
Compressed air	Compressor sited away from teaching space, receiver, refrigerant dryer sized for local humidity, ring main with drop legs and drain points	Moderate for the ring main, high for the plant space
Cooling and ventilation	Sized for the heat rejected by the equipment, not just for occupancy	High, and undersized cooling shows up only in April

Size compressed-air treatment for the manufacturer’s required quality and the site’s ambient conditions. Locate ventilation discharges using a re-entrainment assessment. Establish chemical and biological waste segregation before designing drains, and reserve data routes with suitable separation from power cables.

Standby supply and the load-shedding question

Classify each load by the consequence of interruption and its safe shutdown requirements. Coordinate instruments with their cooling, extract, gas and control auxiliaries. Heaters and motors cannot automatically be excluded from essential power if they support a critical process or safety function.

Floor loading, vibration and the quiet corner

Structural decisions are the truly irreversible ones, and laboratory loads are not what a general office floor is designed for.

• Water is one tonne per cubic metre. A flume, a bench sump, a settling tank or a pilot plant vessel imposes a point load a standard slab may not have been checked for. Give the structural engineer operating weights, not shipping weights.
• Prefer the ground floor for heavy and wet laboratories. It solves loading, vibration, drainage and access in one decision.
• Reserve a low-vibration, low-interference position if the institution has any ambition towards electron microscopy or precision metrology. A scanning electron microscope is sensitive to floor vibration, to stray magnetic fields from nearby cables and transformers, and to acoustic noise. A slab-on-grade corner away from lifts, plant rooms, road traffic and the electrical riser is worth reserving even before the instrument is funded, because no amount of money afterwards moves the lift shaft.
• Plan the route for plant on the roof. Extract fans, scrubbers and compressors need access, a maintenance walkway, structural provision and anti-vibration mounts. A scrubber plinth added as an afterthought to a finished roof is a leak waiting to happen.
• Check the lift, the stair turning circles and the door widths against crated dimensions before the shell is built, and where the numbers do not work, design in a removable panel or a lifting beam.

Storage, and why every laboratory is short of it

Ask any laboratory manager what they would change and storage comes up more often than equipment. Storage takes floor area away from the visible teaching function, so it is the first thing trimmed when the plan is squeezed.

1. A separate chemical store with segregated cabinets, ventilation and a lockable door, not a cupboard at the back of the teaching room.
2. A cylinder store outside the building, shaded, ventilated, with cylinders restrained and full and empty separated.
3. A technician's workshop or preparation room adjoining the laboratory. Setting up an experiment for twelve groups is not something that can be done in the room while a class is in it.
4. Storage for accessories that are not in use, plus a spares cupboard with an inventory. A hydraulics bench with eight accessories needs somewhere for seven of them that is not the floor, and imported spares only protect you if they can be found.
5. Somewhere for student bags near the door, outside the working zone. Without it, bags go under benches and become a trip hazard in exactly the wrong place.

Commissioning: hold retention against tests, not against delivery

Write the acceptance criteria into the contract at tender stage. Once the building is handed over and the retention released, your bargaining position is gone.

• Electrical: earth resistance measured and recorded, residual current devices tested, every board way labelled against a drawing left in the room, interlocks demonstrated.
• Extraction: face velocity measured and recorded per fume cupboard, discharge point verified against the drawing, make-up air demonstrated with doors in the normal position.
• Water and drainage. Use an approved commissioning method to verify outlet flow, leak-tightness, drainage capacity and collection/treatment routes. Do not flood an occupied laboratory as an improvised test.
• Compressed air and gas: pressure and dew point at the furthest drop leg rather than at the receiver, a leak test on reticulated gas lines, and detection commissioned with the alarm routed somewhere a person will hear it.
• Equipment. Commission safely with authorised staff before student use. Demonstrate agreed experiments and acceptance criteria, including instrument limitations and measurement uncertainty.
• Documentation: operation and maintenance manuals, as-built drawings, test certificates, spares list and a training record for named staff, handed over as a condition of final payment.

What it costs to change your mind

Decision	Change during design	Change during construction	Change after handover
Room size and door widths	A drawing revision	Structural rework	Usually impossible
Drainage falls and gully positions	A drawing revision	Screed rework, some delay	Cut the floor, lose the finish
Fume cupboard duct route	A drawing revision	Riser and ceiling coordination	Often no route exists at all
Electrical board capacity and spare ways	Marginal cost	Board replacement	New submain and containment across a live building
Earthing arrangement	Marginal cost	Moderate	Disruptive and usually compromised
Bench positions and services outlets	Free	Moderate	Surface conduit and trailing leads
Storage and preparation room	A planning decision	Loss of teaching area	Corridor cupboards and clutter

Every row in the right-hand column is a laboratory somebody is working in today. The items that cost the least to decide correctly are the ones that cost the most to fix, because they are buried in the fabric.

The equipment schedule should remain a controlled design document through construction, commissioning and future expansion.

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