Thursday, August 1, 2013

ISO Signage Directive: Clear Pictograms for Universal Understanding

The British trade group Industry Committee for Emergency Lighting (ICEL, has issued a Technical Statement that clarifies the recent change in Emergency Exit Signage in the UK.  It is excerpted here with additional commentary as it applies to US signage.  Note that the US is moving towards the ISO 'running man' standard for egress signage and the common red or green  EXIT  sign is gradually be replaced in US buildings.

It is not enough that a safety sign can be seen. It is essential that each sign is quickly understood and that an installation of signs quickly and clearly conveys their intention and continues to confirm the message.

Research has identified that the key requirements for an acceptable safety sign are:-
  • Conspicuity:  The capacity of a sign to stand out or be distinguishable from its surroundings and thus be readily discovered by the eye.  It is the noticeable contrast between a sign and its background, attributed to an exogenous (unplanned) or andogenous (planned) mind-set, with the display having features that attract attention to the sign.  Conspicuity is considered a subjective outcome.
  • Visibility:  The physical attributes of a sign and its contents that allow for detection at a given distance, although legibility may be uncertain.  Visibility is considered an objective stimulus.
  • Legibility:  The physical attributes of a sign that allow for differentiation of its letters, words, numbers, or graphics and that directly relate to an observer’s visual acuity.  Legibility is considered an objective stimulus.
  • Understandability:  That which enables the observer to correctly perceive the information content of letters, numbers or symbols grouped together, or other meaningful relationships on the sign.  Understandability is the character of a sign that leads to comprehension of its intended message, and depends on legibility and other considerations of contents and time restraints.  It is considered a subjective outcome.
When considering a design for an effective escape route it is important that the exit path and any potential obstacles are well illuminated (the centre line of any escape route should be lit to a minimum of 1 Lux [the US NFPA 101 Life Safey Code uses a similar, but different standard]) and the route should be marked with well positioned signs that clearly indicate the direction towards a final exit and on to the “place of safety”.

The signs should be positioned so that each sign is always within a readable viewing distance and each sign shall be located so that it is visible to reconfirm the correct route at every intersection or change of direction so that evacuees can move along the escape route quickly and safely.  However, in some environments (public buildings, retail areas, etc.) there may be a great number of sign boards, building furniture and visual obstacles that could confuse evacuees in an emergency.  This is why safety signs must be easily seen and understood and, in today’s multinational society, it is essential that the meaning of signs does not rely on any specific language.

The Legal Situation

Standardization across Europe was one method of increasing a wider understanding of safety signs. Therefore, the European Community (EC) Safety Signs Directive (92/58/EEC) was published and adopted as ‘The Health and Safety (Signs and Signals) Regulations’ in England during 1996. This piece of legislation set out simple ‘Pictogram’ sign formats to be used within the European Community.

The Regulations showed the intrinsic features required for emergency escape (egress) signs as being white on green, with pictorial symbols of a running man, a direction arrow and a door.  These intrinsic features avoided the use of words in any of the escape signs and set out escape route guidance by showing the running man with an arrow down for when the escape route went straight on, arrow right for right turns and arrow left for left turns.  The Regulations simplified the vast range of text signs that had previously been used.

The only problem with the EC Safety Signs Directive was that the pictograms supplied were of a different format to those shown in ISO documents and some National Standards such as BS 5499. Here are the three formats currently seen in use in the UK:

In 2011, it was decided by many of the National Standards bodies to consider adoption of a single pictogram format as shown in ISO16069.  The British Standards Institute (BSI) adopted this format in the latest edition of the BS5266:2011 standard, which is considered the ‘de-facto’ emergency lighting standard for the UK.

The members of the Industry Committee for Emergency Lighting (ICEL) recognized that a further change in sign format could cause further confusion within the already confused market and therefore decided to introduce the ICEL Clear Sign Campaign.  It is a UK legal requirement for businesses to conduct risk assessments for fire safety and evacuation and it is of course vital that the emergency escape signs are of a legal format.  The current position includes the following key issues:
  • Text only signs (like the common "EXIT" or "SORTE") are not legal and should have already been replaced.
  • BS5499 Pictogram signs (with or without supplementary text) are legal but should only have been used when expanding an installation already incorporating similar signs.
  • Pictogram only signs with the same format as shown in The Health and Safety (Signs and Signals) Regulations / EC Safety Signs Directive (92/58/EEC) are legal but should not be mixed with other sign formats on any installation.
  • From 2012 the new ISO16069 Pictogram signs will also be legal but again should not be mixed with other formats on an installation.
  • The latest proposals do not only identify the ISO16069 sign format, there are also references to ISO 3864-1 and ISO 3864-4 to provide detailed information relating to the safety color and contrast color.
The images above show the different appearance of the ISO Pictogram symbols used in these EXIT signs but the key differences between the Health and Safety (Signs and Signals) Regulations / EC Safety Signs Directive (92/58/EEC) pictograms and the ISO 16069 versions include:
  • ‘Straight on’ is depicted by an arrow facing up in ISO 16069 (and in BS 5499) whereas the Safety Signs and Signals Regulations do not state which way the arrow should be used.
  • ISO 16069 allows the use of supplementary information such as diagonal arrows (for stairs up or down) and in certain instances the use of text (e.g. to distinguish between a normal exit that may also be used for escape and an exit that is perhaps intended only for emergencies and may lead to an exit door that is fitted with a security alarm).
Initially, the best advice is to use internally illuminated emergency sign luminaires with the minimum number of sign formats to avoid confusion.

Almost all escape route scenarios can be clearly indicated with the basic ISO 16069 pictogram signs conveying the messages ‘straight on’, ‘go left’, ‘go right’.

The technical features required for these signs are:
  • The luminance of any area of safety color of the sign shall be at least 2 cd/m².
  • Within either the contrast color white or the safety color, the minimum luminance divided by the maximum luminance shall be greater than 0.2.
  • The ratio of the luminance Lcontrast to the luminance Lsafety color shall be not less than 5:1 and not greater than 15:1.
  • Signs shall be illuminated to at least 50% of the required luminance within 5 seconds and full required luminance within 60 seconds (this is significantly different from the US standard where the signs must remain continuously illuminated).
Although these factors can appear to be complicated, the principles are well known by reputable emergency lighting specialists and should be assured by specifying products supplied by ICEL member companies.

However, Local Authorities and Fire Authorities can require new installations to be of either format – EC Safety Signs Directive or ISO 16069 until the situation is resolved by an amendment to the Directive – So check to be sure you are supplying the correct format for your facility.

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