VHA National Center for Patient Safety
A Brief History of Indicating Valves for Fire Protection
What are indicating control valves and why would they be helpful? by Joseph M. DeRosier, P.E., C.S.P.
The property insurance industry learned the value of indicating type control valves the hard way, through their loss experience. Automatic fire sprinkler systems were developed in the late 1800's for the purpose of protecting insured property from fire loss. These early sprinkler systems were nothing more than fixed piping with holes drilled into the pipe to permit water to escape as it was (manually) pumped in.
Another early sprinkler system involved the use of partially water filled glass balls that were suspended from the ceiling. In theory the glass ball would break during a fire discharging a limited amount of water onto the fire (more likely the floor).
The development of the fusible link fire sprinkler permitted fire sprinkler systems to operate automatically when the systems were connected to a reliable water supply. Water could be introduced and kept in piping without it discharging and damaging the building or building contents.
In order to perform maintenance on these new automatic systems and permit them to be shut off in the event of a broken pipe or the operation of a fusible link sprinkler, a control (shut off) valve was installed between the sprinklers and the water supply. While necessary for the reasons just stated, this valve also permitted the water supply to be inadvertently turned off.
Closed valves started to show up as contributing factors to high dollar loss fires. The insurance industry, paying the tab for the losses, looked for a solution. What followed was the development of an "indicating" water supply control valve.
These indicating valves employ a rising stem, "open/shut" target, holes, or another clearly visible system to indicate when the valve is in fully open position. The use of these indicating valves in conjunction with a robust inspection program reduced fire losses in sprinkler protected structures.
Take a look at one of your oxygen cylinders, is the shut off valve on the cylinder open or closed?
