Have a look on the HSE web site you may find a free down load booklet as jasper has mentioned, the Qu below is taken from the site.
Q3 We inspect service-industry sites (e.g. nail technicians) which handle flammable solvents like acetone. What can we say about the amounts in the customer area, or precautions against spillage, or zoning?
A3 Highly flammable solvents such as acetone release vapours, which are easily ignited. Where possible less flammable solvents should be used in preference. Where highly flammable solvents are used and the public are present, it is difficult to maintain constantly an effective control over all sources of ignition, such as smoking, or portable electronic equipment. Consequently hazardous area classification is not appropriate. Instead, it is better to limit the amounts present, to use containers that minimise the risk of spills during transfer, and in particular to avoid containers that will break if knocked over. The quantity held in the workroom should be limited to the amount used in half a day’s work.