To satisfy the management of health and safety regulations including fire safety it is a requirement to inform, identify , locate, instruct and educate.. Appropriate use of safety signs are one way to satisfy these requirements and resolve liability.. It is for the Responsible Person to assess the risk of not using signs as a minimum requirement..... The responsible person can always manage this problem another way... Why have these types of doors?? Why are we securing fire exits?? Why not tell everyone where they are and what they are for? Formal training etc etc.
Break Glass Units are not always sited in exactly obvious and conspicuous positions... I have noticed the proliferation of these devices for purely security reasons that have an ordinary override switch as well as an emergency glass operating system, I have noticed Break Glass Units for Disability Assistance and Emergency call location. Each case will be different, however there is a correct graphical symbol for emergency call point so if you feel it is appropriate to inform, identify, locate, instruct, and educate this safety sign may be used with appropriate supplementary text and will be deemed to satisfy the minimum requirements.
You should not blame the number of signs that are required as this is an indication of the amount of information you need to understand this particular buildings escape strategy...To reduce the number of signs question the strategy.