"PA12DRVR...your story reminds of a buddy who was in the Navy during the 60's-70's and told of what they told him if they ever 'heard' steam escaping. Invisible and that stream was hot enough & escaping fast enough to cut a body in half...told to take a broom and wave it slooowly around and found when the broom was cut in half...don't know how true that one was".
Whether or not it was the best, most efficient, or safest method, that method (or a variant as far as what was waved) was very true "back in the day". During the same piping installing job, one of the more discrete activities was to run each boiler up to 1XX% of pressure / temp / flow and then do the same for each turbine as part of the prep for start up. All of that required that various gas and steam control valves were flowing, while within design parameters, at 1XX% of normal operating flow. That flow, while not indicating any problem, generated a noise that was close enough to escaping superheated steam that checks were needed for leaks. The procedure was to walk down the pipe chase and wave (it was actually a bit more prescribed than that) the broom in a consistent manner, then, barring any leak indications, walk through the pipe chase again with a gas detector held X", Y", and Z" above the floor to seek out gas leaks that might not have got to the level of triggering the primary detectors.
The dual-redundancy aspect was that there were special pressure and temp gauges put in the feed and outflow piping where such gauges provided circa .25 psi gradations and ??? 1 degree??? gradations. Once steady state was reached, which had to be maintained for IIRC 12 hours, any change of more than 2-3 psi and 8-10 degrees required oversight, possibly intervention, and ultimately possibly shutdown. The lower guys on the totem pole (remember, this was back in the day) got to argue who got the broom waving duty (more on edge but shorter) vs. the gauge watching duty, safer but BORING.
The "broom" was actually a rube goldberg frame with visqueen and paper....would still be cut by steam, but would pickup moisture if the leak was microscopic. Either result shut down the boil in process.
Good times from decades ago.