Laboratory Worktops

Laboratory Worktops

Most worktops are fabricated to a customer’s own specification and are supplied in an easy to assemble form with the minimum of joints. All assemblies are laid out in our works to ensure dimensional accuracy, matching of components, flatness of joints and overall appearance. This way you can be assured that all items will fit together accurately on site.

Simmons worktops are cast in a nominal thickness of 15mm and in lengths up to 3000mm and widths up to 1000mm (for special orders, some worktops can be cast at up to 1300mm wide). Worktops can be cut with a square edge, have an edging profile fitted or have a radius edge machined on to them.

Worktops are cast in solid homogeneous form and so cannot delaminate and will exhibit the same excellent chemical resistance throughout their entire thickness.  Worktops are mechanically strong and as such do not require any sort of backing material. We recommend continuous supports to the front and rear with cross members spaced at a maximum of 800mm.

Our range of Laboratory Worktops

Standard square edged

Laboratory Worktop Standard Square Edge

Worktops have a very small chamfer to top and bottom edges. Cut edges will be cleaned up but will not have the same gloss finish as the top surface.

Edged worktops

Laboratory Worktop Edged

For safety purposes a containment edging can be provided to any worktop. This illustration shows a no.1 front edging fitted onto a worktop. Other edgings or upstands of the customer’s choice can also be used. Full details on the range of edgings and upstands available can be found on here.

Radius Edged

Laboratory Worktop Radius Edged

Where specified, Simmons can supply flat worktops with a radius machined onto the top edge. Machined edges will be cleaned up but will not have the same gloss finish as the top surface.

Our standard colours are:

The colours shown on this website are a guide only and cannot be guaranteed to match the colour of components supplied by Simmons.

Grey

White

White

Cream

Black

Black

Dark Grey

Chemical Resistance

(24 hour sport test. Based on BS EN 438-2:1991).

Acetone

Unaffected

Acetonitrile

Unaffected

Ammonium Hydroxide – 28%

Unaffected

Aqua regia

Unaffected

Benzyl alcohol

Unaffected

Chloroform

Unaffected

Chloroform – 100%

Unaffected

Chromic acid pickle (*1)

Unaffected

Dicholoromethane

Surface attack

Dimethylformamide

Unaffected

Ethyl acetate

Unaffected

Formaldehyde – 37%

Unaffected

Hydrochloric acid – 30%

Unaffected

Hydrochloric acid – concentrated

Unaffected

Hydrofluoric acid – 40%

Slight bleaching

Hydrogen Peroxide

Unaffected

Methanol

Unaffected

Nitric acid – 70%

Very slight bleaching

Nitric acid – concentrated

Slight yellowing

Nitric acid – fuming

Attack and staining

Perchloric acid – 0.1N

Unaffected

Phosphoric acid – concentrated

Unaffected

Potassium hydroxide pellet (*2)

Unaffected

Sodium hydroxide – 50%

Unaffected

Sodium hydroxide pellet (*2)

Unaffected

Sodium hypochlorite

Unaffected

Sulphuric acid – 70%

Unaffected

Sulphuric acid – concentrated

Surface attack

Xylene

Unaffected

Mechanical Properties

Tensile strength

85 N/mm²

Tensile Modulus

10,500 N/mm²

Elongation at break

0.8%

Flexural strength

112 N/mm²

Flexural Modulus

10,000 N/mm²

Compressive strength

190 N/mm²

Coefficient of linear thermal expansion

34 x 10⁶

Water absorption – 24 hours at 23ºC

5–10 mg (0.06–0.068%) ISO 62 (1980)

Thermal Properties

Thermal Shock

2000 cycles (90 sec. at 75ºC, 90 sec. dwell, 90 sec. at 15ºC)
No effect
Should not be used with dry-ice or liquid nitrogen

Smoke Emission

Low Smoke Emission – BS 6853 1999 App. D Clause d.8.4
Result – Ao(on) 8.75, Ao(off) 10.41

Flammability

Class 0

Thermal Decomposition

350ºC

Glass transition temperature (Tg)

120 – 130ºC

Radioactive Decontamination

Decontamination factor (geometric mean)

5598.0

Deviation factor

1.25

Ease of radioactive decontamination classification

"Excellent"

Installation and Maintenance

Storage of Tops and Bases

All tops and bases should be stored flat. Under no circumstances should components be stored leaning against a wall as this can cause bowing.

Corner protectors are provided to protect tops during transportation and handling. If components are to be stored for any period of time the corner protectors should be removed.

Worktop Supports

Simmons recommend that continuous rails be provided to the front and rear of worktops. If a section is to be unsupported the span should not exceed 800 mm.

Fume cupboard bases should have continuous support to the perimeter. Any bases longer than 900 mm should also have central supports.

Epoxy Resin Grout

Grout is supplied as a pack of two components :- resin and hardener. Once mixed the grout has a workable life of approximately 5 minutes. It is therefore essential that only a manageable amount of grout is mixed at one time, and that all preparatory work is done before mixing.

The resin and hardener should be measured out at the ratio stated on the containers onto a mixing board. When ready for use this should be thoroughly mixed using the wooden sticks provided until the two components are homogeneous.

Please note that a minimum room temperature of 5°C is required to initiate the cure cycle for the grout. The useable life of the grout will vary with the ambient temperature. The warmer the room the quicker the reaction.

It is recommended that Latex gloves are worn whilst using epoxy resin grout components and cellulose thinners.

Drilling and Cutting

Small holes can be drilled in Simmons’ epoxy resin tops using masonry or tungsten carbide tipped drills. Larger holes will require the use of diamond plated holesaws.

Small cuts can be made using diamond plated jigsaw blades (which can be purchased from Simmons if necessary). If more substantial amounts of cutting, or cuts with a cosmetic finish are needed, the tops should be returned to Simmons for factory cutting.

Jointing Tops

Joining Worktops Image

 

List of Tools and Equipment required:-

  • Cellulose Thinners
  • Clean Cloths / Wipes
  • Vinyl Tape
  • Long Sash-Clamps
  • G-Clamps
  • Levelling Blocks
  • Sharp Flat Chisel
  • Steel Rule
  • Latex Gloves

All joints are machined for a biscuited joint. All biscuits and grout for making the joint are supplied with the tops.

Joints should always be cleaned and degreased with cellulose thinners before commencing any work. Vinyl tape should be applied to the top surface adjacent to the joint as close to the edge of the top as possible. The two sections of top should then be carefully lined up and pushed together until there is a gap of approx. 2 – 3 mm.

A mix of grout should then be prepared as described above. When completely mixed this should be applied to the abutting edges of the tops. The tops can then be pulled together with sash-clamps until the grout/joint line is less than 1 mm wide. The narrowest joint is always the strongest joint.

It is recommended that the front edge of the top be carefully levelled off and clamped with levelling blocks and G-clamps either side of the joint. The top must be held together with sash-clamps while the grout goes off. Excess grout squeezed out of the joint should be levelled off to the top of the vinyl tape using a flat / straight edge (e.g. steel rule).

After 5 minutes the vinyl tape can be carefully removed ensuring that the grout in the joint is not damaged. After a further 4 – 5 minutes the grout will become slightly rubbery. The joint should then be wiped down with cellulose thinners with strokes going across the joint (not along it).

General Maintenance

As with all worktops a reasonable standard of laboratory housekeeping will help to keep the worktops in good condition. All spillages should be cleaned up as soon as possible. Staining agents and aggressive chemicals should not  be allowed to sit in contact with the tops for a prolonged period of time.

Areas of chemical attack or staining can be removed with a polishing compound or very fine abrasive paper, but it should be stressed that this will alter the finish of the surface. Performance will not be affected.

The use of a wax furniture polish will help to retain the gloss finish.

Components should not be exposed to dry-ice or liquid nitrogen and heat insulation pads should be placed between a top and a steambath or hotplate to prevent thermal stress.