Safety device for fluid ends

A safety method, comprising:

• shutting down a fluid end by stopping pressurized fluid flow through the fluid end and draining pressurized fluid from the fluid end;
• when the fluid end is not operating, viewing a safety device that is coupled to the fluid end to determine whether there is still pressurized fluid within the fluid end at a pressure above a predetermined pressure, wherein the safety device comprises an outer housing and a visual indicator at least partially disposed within the outer housing that is movable between a first position to a second position, wherein the outer housing comprises a top housing coupled to a bottom housing, wherein a lower end of the bottom housing has an outer diameter smaller than an outer diameter of an upper end of the bottom housing, wherein the lower end of the bottom housing is recessed within a body of the fluid end, and wherein the safety device further comprises a biasing member disposed within the bottom housing such that the biasing member is at least partially disposed within the body of the fluid end;
• if the visual indicator is viewed as being in the first position such that the visual indicator is retracted into the outer housing, then further comprising accessing internal components of the fluid end by removing a cover of the fluid end;
• and
• if the visual indicator is viewed as being in the second position such that the visual indicator is extended out of the outer housing, then further comprising draining the pressurized fluid again from the fluid end until the safety device is viewed as being in the first position.