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.
On handover day somebody notices that the double doors into the main laboratory are narrower than the crate the fluidised bed unit will arrive in, that the only three-phase outlet is at the wrong end of the room, and that the fume cupboard duct rises through the ceiling into a void with no route to the roof. All three were decided on a drawing eighteen months earlier by people who had never been told what would go in the room. All three now cost more to fix than they would have cost to get right.
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.
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.
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.
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.
| 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 | A tested earthing arrangement with a recorded measured value at handover, plus a clean reference for instrumentation | Very high. Retrofitting an earth into a finished building is disruptive and often compromised |
| Water supply | Pumped supply from building storage rather than direct mains, isolating valve and hose union per position, non-return valves | Moderate for a branch, high for a new riser |
| Drainage | Correct falls, chemical-resistant material, trapped gullies, an interceptor or dilution pit | 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 |
Three of these deserve extra attention in Bangladeshi conditions. Compressed air dryers are routinely undersized, and in the monsoon a wet air line will ruin pneumatic valve positioners and any experiment that depends on them. Extraction discharge points are routinely placed too low, and the exhaust re-enters through the windows of the floor above. And the interceptor pit on the laboratory drain is routinely omitted because it is invisible, which leaves the institution with no containment when something is spilled. Add to that a data cabling route in its own containment, separated from power, for every computer-controlled rig position.
Decide, at design stage and in writing, which circuits stay live when the mains drops. The economical arrangement is rarely to back up the whole laboratory. Instrumentation, control panels, data acquisition, computers, gas detection, fume cupboard extract and any refrigerated storage justify backup. Motor loads and heaters usually do not. Getting this into the design means separate final circuits and separate boards, which is easy on the drawing and awkward later.
Structural decisions are the truly irreversible ones, and laboratory loads are not what a general office floor is designed for.
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.
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.
| 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.
By the time the equipment arrives, ninety per cent of what the laboratory can ever do has already been decided by the building.: Vvon Technologies installation team