HC Deb 20 February 1990 vol 167 cc616-7W
Mr. David Shaw

To ask the Secretary of State for Trade and Industry if he will list the potential dangers to health known to his Department from the use of consumer products which can produce flicker or stroboscopic light sources with a flicker rate in excess of five flashes per second; and if he will issue a statement about those potential dangers of such products.

Mr. Forth

It is known that the direct exposure to flicker or stroboscopic light can create a susceptibility in a small proportion of the population—about one in 10,000—to flicker sensitive epilepsy. This can occur within a range of frequencies from five to 65 flashes per second which can be generated by television or amateur cine projection equipment. Additionally, of course, there is a physical danger that rotating equipment under stroboscopic light can be perceived to be stationary when it is in fact moving rapidly.

However, I am not aware of evidence where these effects have become a general threat to safety in the use of consumer products.

Mr. David Shaw

To ask the Secretary of State for Trade and Industry if he will list those consumer products on sale in the United Kingdom, of which he has knowledge, which are capable of producing a flicker or stroboscopic light source with a flicker rate in excess of five flashes per second.

Mr. Forth

[holding answer 16 February 1990]: The information is not available in the form requested but there are two groups of products which are capable of producing regular pulses of light at a frequency greater than five flashes per second. The largest group includes lighting products such as fluorescent tubes or television screens where flicker is unintended but nonetheless produces flicker rates varying between 30 and 100 pulses per second, arising from the electrical mains frequency or screen scanning frequency. The second group covers products where the stroboscopic effect is intended, as with equipment for adjusting motor engine timing dynamically, where the strobe frequency is variable in a range upwards of about 10 pulses per second.

Any piece of continuous lighting equipment can, of course, he made to flash for effect, as in the case of discotheque lighting. Camera equipment normallly used for single flash operation can also create a stroboscopic effect with a series of flashes when used with a film motor drive.