{"id":690,"date":"2015-03-20T18:58:33","date_gmt":"2015-03-20T18:58:33","guid":{"rendered":"http:\/\/www.saving-light-bulbs.co.uk\/blog\/?p=690"},"modified":"2016-06-02T17:41:32","modified_gmt":"2016-06-02T16:41:32","slug":"how-many-emergency-lights-are-needed","status":"publish","type":"post","link":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/how-many-emergency-lights-are-needed\/","title":{"rendered":"How many Emergency lights are needed?"},"content":{"rendered":"

The Guidelines in Brief<\/strong><\/p>\n

The rules and regulations around emergency lighting are complex and whilst I will not attempt to cover all aspects here I will just bring out a few salient points.<\/p>\n

In the eventuality of a power failure the emergency lighting must come on for a minimum of 3 hours. This can be achieved through 2 types of lights:-<\/p>\n

1. Maintained Lights , where the existing light has a backup battery which will be automatically turned on in the eventuality of a power failure.<\/p>\n

2. Non-Maintained Lights, which are never on unless there is a power failure and then will light for 3 hours.<\/p>\n

The requirement then in broad terms is to provide a minimum of 1 Lux illumination along all the escape routes. This can be reduced to 0.5 Lux for other areas but in most cases experts prefer to keep the level to 1 Lux in all areas as you are never sure which route might become an escape route if objects are left in a planned escape route.<\/p>\n

The Non-Maintained Emergency Light<\/strong><\/p>\n

A cost effective and aesthetically pleasing way to fit a room with emergency lights is to use small non-intrusive emergency lights like these 3w emergency light<\/a><\/p>\n

\"2w_emergency_3hr_01\"<\/a><\/p>\n

The lights is powered by its own battery back up unit and driver so that it is automatically lit in the eventuality of a power failure.\"2w_emergency_3hr\"<\/a><\/p>\n

These are cost effective and efficient but how many do you need in a room and what should the spacing be?<\/p>\n

Spacing of Emergency Lights on a Square Grid<\/strong><\/p>\n

We did some actual tests with a room with a ceiling height of 3.4m and measured the LUX level with an accurate Lux meter of a single light and then here I apply some mathematics to calculate the spacing needed to provide a minimum level of 1 Lux.<\/p>\n

The lights used was have a lumens output of 110lm.
\nThe distance from the position on the floor directly underneath the downlight, to where light level was 1 Lux was 2.9m and to 0.5 Lux was 4.1m.
\nThis provides the size of circle that is always lit to these levels in a dark room. However with a square grid spacing then some trigonometry is needed to work out the spacing.
\nThe maximum spacing between 2 lights would then be 4.1 x cos45 x 2 = 5.8m.
\nAt the edge of the room this is significantly reduced as there are no other lights to contribute to the light level and accordingly the maximum distance would be 2.9 x cos45 = 2.05m .<\/p>\n

Spacing of Emergency Lights on a Hexagonal Grid<\/strong><\/p>\n

If the second row of lights is spaced to be midway between the first row then a more efficient spacing can be achieved and consequently less emergency lights are needed in the room. The calculation is as follows:-<\/p>\n

The maximum spacing to achieve 1 Lux would be 4.1 x cos30 x 2 = 7.1m. The distance from the wall would remain the same but you would need to add an extra light for every other row so this means for a small room this might prove inefficient.<\/p>\n

Clearly tests of Lux levels need to be performed but these measurements should provide some starting guidelines.<\/p>\n","protected":false},"excerpt":{"rendered":"

The Guidelines in Brief The rules and regulations around emergency lighting are complex and whilst I will not attempt to cover all aspects here I will just bring out a few salient points. In the eventuality of a power failure the emergency lighting must come on for a minimum of 3 hours. This can be … Continue reading How many Emergency lights are needed?<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-690","post","type-post","status-publish","format-standard","hentry","category-lighting-design"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/posts\/690"}],"collection":[{"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/comments?post=690"}],"version-history":[{"count":1,"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/posts\/690\/revisions"}],"predecessor-version":[{"id":921,"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/posts\/690\/revisions\/921"}],"wp:attachment":[{"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/media?parent=690"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/categories?post=690"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.saving-light-bulbs.co.uk\/blog\/wp-json\/wp\/v2\/tags?post=690"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}