Safety Helemt Lifespan guidlines

As per ANSI Z89.1, these are recommended useful service life guidelines for hard hats/safety helmets.
JSP’s safety helmets experience suggests that a useful service life of 6 months to 2 years is most likely. However, if the helmet is treated with care and kept in suitable conditions, JSP would expect the maximum useful service life to be up to five years. The service life begins when the helmet is placed into service.

Storage – the maximum shelf life on an unused industrial helmet is five years , as long as it has been stored in reasonable conditions (i.e. not exposed to extremes of temperature, moisture or light). Service Life
All helmets include a date code that is molded into the underside of the shell’s brim,showing the year and month in which that specific shell was manufactured. Therefore, we would not expect to see a helmet in service that was more than 10 years old.

For example...A helmet delivered in March 2015 with a manufacturing date code of December 2014 could be stored in a warehouse until December 2019, and then used in service until December 2024 if the relevant daily inspection and maintenance is carried out. If this same helmet was first put into service in April 2015 , JSP would recommend that it was used no later than April 2020 ( assuming the relevant daily inspection and maintenance is carried out). Certain materials are susceptible to damage from ultraviolet light and/or chemical degradation... and helmets are not exception. Periodic visual examinations should be carried out on all industrial helmets, especially those worn or stored in areas exposed to sunlight for long periods. Ultraviolet degradation may first manifest itself in a loss of surface gloss (called chalking or discoloration). Upon further degradation, the surface will craze or flake away, or both. At the first appearance of any of these phenomena, the helmet should be replaced. Under no circumstances must a component other than a JSP component be used on a jsp helmet. The helmet may be cleaned with the use of soap and warm water and dried with a soft cloth. The helmet should not be cleaned with abrasive substances or solvents, and must not be stored in direct sunlight or in contact with any solvents.

JSP Industrial Helmet – Marking Do not apply paint, solvents , adhesives or self -adhesive labels, except in accordance with the instructions from the hard hat manufacturer. It is acceptable to use a Sharpie Fine Point Permanent Marker using ink dyes containing n -propanol (71 -23 -8), n -butanol (71 -36 -3) and diacetone alcohol (123 -42 -2). This type of pen should only be used on the peak or the “shield” part of the front of the hat. Use of other types of marking effect will invalidate any warranties

What colour safety helmet should you wear on site ?
Build UK have devised a safety helmet colour code that some sites make use of which is. 
White helmet for Site Managers, Competent Operatives, or Vehicle Marshals
Orange helmet for slinger or signaller
Black helmet for Supervisors
Blue helmet for all other site workers 
It is important to realise that this isn't a legal requirement, though more and more sites are adopting this colour code for safety helmets use on sites.