Hi John no I didn’t know they were colour coded what years are you talking about? In the BR 1950 Rule Book I couldn’t find anything about colour coding unless I’ve missed it but it states that they were date stamped with the month and year of manufacture the oldest being used first and the unused one’s to be returned to the Stores Department at the expiration of three years from the date stamped or up to five years where authority is given but “ Detonators must not under any circumstances be used after there are five years old “ are you meaning by seven year cycle that they could be used up to seven years old before they were discarded?
My copy of the 1972 "General Appendix" says that for the period 1st July-30th June, the colour codes were:
1966/67: White; 67/68: Orange; 68/69: Red; 69/70: Green; 70/71: Grey; 71/72: Yellow; 72/73: Blue
The colours then restart in 73/74 with White.
....Dets used to be painted different colours to indicate the expiry date but that hasn't been done for a long time, these days they’re all painted yellow and have a sticky label showing the expiry date stuck on them.....
That ties up with the three dets we have at St Albans South which are all yellow and date from 2011. We show them to visiting parties, particularly the younger ones, to explain they are dangerous, if they ever find one lying about it must not to be touched and to call an adult immediately.
Additional Info: Detonators in detonator placers needed to be changed every two months, according to the 1972 General Appendix "...on the first Monday in each alternate month and a record made in the Train Register when the change is made.". Station managers were also charged with making frequent checks on the detonator placers and each signalman on starting his daily duty was expected to check the placers were in working order by operating the lever or stirrup for each placer.