Lab Consumables and Safety Equipment - A Tender Checklist

Consumables are the part of a laboratory tender that gets written last and disputed first. Equipment is bought once and inspected on delivery; consumable items are bought every year, opened by a technician who was not in the room when the schedule was written, and rejected when the grade is wrong. This checklist covers what a lab consumables list should contain, how to specify the items that are most often misquoted, and what safety equipment a technical committee expects to see before it will pass a laboratory as fit for use.

Why consumables belong in the tender, not in petty cash

Most institutions buy equipment through a tender and consumable materials through local purchase. That works until an audit asks why the same item was bought at four prices in one year. Putting consumables into an annual rate contract fixes the price for the year, fixes the grade, and gives the store a single supplier to chase when a batch fails.

Three things make a consumables schedule work:

• Unit of issue stated for every line. "Filter paper, 100" means a hundred sheets to one bidder and a hundred boxes to another. Write "pack of 100 circles, 110 mm" and the ambiguity disappears. This single omission causes more bid comparison errors than any other.
• Annual quantity, not a one-time quantity. Estimate from batch size — number of students, groups per batch, batches per year — so the supplier can price a volume rather than a sample.
• Shelf life and batch details for anything that degrades. Stains, reagents, membranes and indicator papers should carry a stated minimum shelf life remaining at delivery, usually two-thirds of total.

Filter paper: the most misordered item in any laboratory

Filter paper is ordered more often than any other consumable and specified less carefully than any other. A tender line reading "filter paper, Whatman No. 1 or equivalent" is not enough, because "or equivalent" is exactly where the argument starts. Specify these four things:

• Qualitative or quantitative. Qualitative paper is for routine filtration and clarification. Quantitative paper is ashless and is the only kind usable in gravimetric analysis, because the residue left after ignition must be negligible.
• Retention and flow rate. State particle retention in microns and whether the flow is fast, medium or slow. Fine retention and fast flow are opposite properties, so asking for both in one line guarantees a substitution.
• Ash content for ashless grades, stated as a maximum percentage.
• Form and size. Circles or sheets, and the diameter in millimetres. Circles are typically 90, 110, 125, 150 or 185 mm, and a Buchner funnel takes only one of them.

The same discipline applies to the related items — folded filter papers, glass microfibre discs, membrane filters with pore size in microns, pH and litmus papers, and the filtration unit or vacuum assembly they are used with. For a filtration unit, state the funnel volume, the membrane diameter it accepts, the material of construction and whether a vacuum pump is included, because it usually is not.

What a lab consumables list should cover, by department

A workable list is organised by department, because that is how the stores issue it and how the departments consume it.

• Chemistry: filter papers, pH and indicator papers, corks and rubber bungs, tubing, wash bottles, reagent bottles, spatulas, crucibles, desiccator plates, cleaning brushes for burettes and test tubes, cotton wool, matchsticks and burner spares. See our glassware guide for the items that sit between consumable and capital.
• Biology: slides and coverslips, stains, mounting media, dissecting pins and boards, gloves, blades, petri dishes, culture tubes, inoculation loops, and the brush sets used for biology practical work.
• Physics: connecting leads, fuse wire, eureka wire, thread, weights, lenses and mirrors that break, graph paper and spare bulbs.
• Civil and materials: filter paper for moisture content work, sieve brushes, moulds, curing tank chemicals, sample bags and marking materials.
• Common: plasticware, gloves, tissue rolls, detergent for glassware washing, distilled water, and disposal bags.

Heating, stirring and water: the small equipment that sits with the consumables

These items are usually tendered alongside consumables because they are replaced on a similar cycle, and they are worth specifying properly.

Lab burner and Meker burner. A Bunsen burner and a Meker burner are not interchangeable. The Meker has a grid head that produces a larger, hotter, more uniform flame and is required where a wide crucible must be heated evenly. State the gas type — LPG or natural gas — because the jet differs.

Hot plate apparatus and laboratory heater. Specify plate size, plate material, wattage, maximum temperature, and whether the control is a simple energy regulator or a thermostat with digital display. A hot plate without a stated maximum temperature is not a specification, and a laboratory heater intended for continuous use should state its duty rating.

Mechanical stirrer. State speed range in rpm, stirring capacity in litres, torque or motor wattage, shaft and impeller material, and whether a stand and chuck are included. A mechanical stirrer and a magnetic stirrer solve different problems — viscous media need the former — so do not let a schedule leave the choice open.

Laboratory water distiller. Specify output in litres per hour, single or double distillation, material of construction, and whether the unit is wall mounted or bench mounted. Output rating is the line item that decides whether a chemistry department spends its mornings waiting for water.

Laboratory humidifier. Required where samples are conditioned to a fixed relative humidity. State the humidity range, control accuracy and chamber volume.

Lab safety equipment: the schedule that gets cut and should not be

Safety equipment is the first thing removed when a tender budget is tight, and the first thing an inspection asks for. A minimum schedule for a teaching laboratory:

• Eyewash station and, for chemistry, an emergency safety shower within ten seconds' reach of the working area
• Fume hood with stated face velocity and a working sash
• Fire extinguishers of the correct class for the hazard present, plus a fire blanket and a sand bucket
• First aid cabinet, stocked, with a named responsible person
• Chemical spill kit appropriate to the chemicals stored
• Ventilated chemical storage cabinet, with acids, bases and flammables separated
• Personal protective equipment in quantity — safety goggles, gloves, aprons and face shields sized for students, not one adult size

Most lab accidents in teaching institutions come from the same few causes: heating a closed vessel, adding water to concentrated acid, unattended burners, mouth pipetting, and broken glassware handled without gloves. Every one of them is addressed by equipment on the list above plus a written procedure. Specify the equipment in the tender and the procedure in the handover documentation, and the inspection becomes a formality.

Frequently asked questions by Naugra Export

What is the difference between qualitative and quantitative filter paper?

Quantitative filter paper is acid-washed to remove mineral content and leaves almost no ash when ignited, so the mass of the residue can be measured accurately. Qualitative paper leaves too much ash for gravimetric work and is used for routine filtration only.

Should consumable items be tendered separately from equipment?

Usually yes. Equipment is a one-time capital purchase; consumables suit an annual rate contract with a fixed price and an agreed delivery schedule. Tendering them together tends to produce a single delivery of a year's stock, which is rarely what the stores want.

How much filter paper should a college order in a year?

Estimate from practical batches rather than from last year's invoice. Students per batch, divided by group size, multiplied by the number of filtration experiments and by batches per year, plus twenty percent for wastage and repeat experiments.

What safety equipment is mandatory in a teaching laboratory?

Requirements vary by state and by affiliating university, but eyewash, fire extinguishers of the correct class, a first aid cabinet, PPE for every student at the bench, and fume extraction wherever volatile chemicals are used are expected everywhere.

Naugra Export - We supply consumables and safety equipment on annual rate contracts alongside laboratory equipment for every department. Send us your consumables schedule and we will return an item-by-item quotation with grades, pack sizes and units of issue stated. Email us at -  h.singh@naugraexport.com