Domestic dishwashers are a cost-effective way of cleaning most glassware for general use in the school laboratory. Specialised laboratory dishwashers offer options for cleaning specialised laboratory equipment, but are generally more expensive. There are a number of points to consider before purchasing a dishwasher for a school laboratory:
- Warranty: Check the warranty on domestic dishwashers to ensure the conditions of ‘normal domestic applications’ use are not breached if a warranty call-out should be needed
- Suitability: for the type of glassware and equipment to be washed:
- Different shaped glassware: Will the water spray reach all areas of the glassware such as narrow necked glassware (flasks, stock bottles and measuring cylinders) and pipettes? Laboratory washers come with specialised washing adapters as extra options.
- Small glassware: The risk of damage to small glassware (such as 50mL beakers) or fragile items from a vigorous water spray. Fragile items are usually placed on an upper shelf.
- Large glassware: The size of the glassware to be washed. Some large measuring cylinders do not fit in either dishwasher type. Can the top rack be removed or adjustable to enable effective washing of very large items?
- Capacity for specialised items: Does the domestic dishwasher have fold-down tines, or removable racks, to create a flat surface on the racks for specialised items e.g. adding test tube baskets (available from Science Suppliers)
- Cutlery Tray vs basket
- Wash cycles:
- Are the wash cycles suitable for the requirements of your lab? Lab washers often have specialised options such as extra rinse cycles and demineralised water rinse. These options are not generally required in most secondary schools.
- How long do the cycles run and how much water do they use
- Energy efficiency and noise levels: Check the specifications for details
- Stainless steel interior: have a number of benefits, for a comparison see http://dishwashersguide.com/tips/plastic-or-stainless-steel-dishwasher-t... However it is essential that items that have been used with corrosive substances are rinsed prior to placing in the dishwasher to minimise the risk of corrosion.
It may be helpful to look at consumer buying guides for general features to consider. E.g.
Domestic dishwashers are generally effective when washing basic glassware used in school laboratories. Cost varies from a few hundred dollars to more expensive models. As schools generally have a limited budget for dishwashers, it is advised that you compare the cost of domestic and specialised dishwashers with any required extra options before purchase.