Page 95 - Boiler_Operators_Handbook,_Second_Edition

80 Boiler Operator’s Handbook

IDLE SYSTEMS panel and control panels so the indicating lights, trans-
formers and the like keep the enclosures dry. Alterna-
For some strange reason people think a boiler plant tively you should check for operation of panel heaters
that’s shut down during the summer or an air condition- or temporary lights installed for that purpose. You can’t
ing system that’s shut down during the winter doesn’t be certain that there’s sufficient power to keep the pan-
need any attention. The contrary is true, they need more els dry so simply open the panels once a week to check
attention because it’s during those periods when the for condensation; any rusting or discoloration says you
equipment isn’t operating that they normally incur the need heaters in them.
most damage. Before you say I don’t know what I’m You don’t want to discover your boiler is full of
talking about consider this: most of the rusting and cor- holes when you try to start it up in the fall so, if the boil-
rosion in heating systems occurs during the summer ers are in wet layup the water should be tested for sulfite
when the boilers are shut down and a typical reason for content and pH weekly and corrected if the analysis
catastrophic failure of a chilled water system is freezing shows the levels to be inadequate for proper storage.
when it’s shut down. Idle equipment deserves just as Boilers without stack caps should have the stacks cov-
much attention as operating equipment. ered if they are above the boiler and stack base access
Idle boilers should be warm (see the section on doors opened if they aren’t so you can be certain rain
standby boilers) or laid up wet or dry. Concerns with isn’t entering the boiler and corroding it. Sometimes that
warm boilers include checking to ensure they’re really isn’t easy to do so it’s more important to see to it that
warm; the temperature of the water at the bottom of the any rain that falls drys out quickly by providing, and
boiler should be the same as the water at the top of the regularly confirming, good ventilation over the metal
boiler. Boilers that are not up to operating pressures and surfaces and up the stack.
temperatures can weep enough to promote high rates of During the winter an idle boiler can freeze up if
localized corrosion so casing drains should be checked the plant is sealed so much that combustion air from
daily to ensure there’s no evidence of the boiler weeping operating equipment is drawn down the stack of the
excessively. idle boiler. That’s why I say stack temperatures should
Idle boilers require more attention because an always be recorded, even on idle boilers. Stagnant water
operating boiler is generating inert gas; it’s less likely piping and the like can also freeze if the cold outside air
to explode than an idle boiler. The fuel oil and gas sup- that’s always drawn into a boiler plant for combustion
ply shut-off valves should be checked to ensure they’re happens to flow over that piping or equipment.
closed and supply pressures after them down to zero. Chillers, cooling towers, and other air condition-
Gas fired boilers should be checked by sniffing at an ob- ing equipment plus any equipment or piping system
servation port or other sampling means to ensure there that contains water should be drained completely when
isn’t any gas leaking into the boiler. it’s idle. If it’s not possible to drain a system completely
The most expensive industrial accident incurred then it should be filled with an antifreeze solution that’s
to date was the result of gas igniting after leaking into guaranteed to prevent freezing at the lowest known
an idle boiler at the River Rouge Steel Mill in February temperature at your plant. If neither of those options
of 1999. The result of that boiler explosion was six dead, are available to you then you have to be concerned with
several injured and over a billion dollars in damage. If freeze protection, checking every piece of idle equip-
the boiler is oil fired the oil burner should be removed ment regularly during the winter months to be certain
or the oil supply piping disconnected from the burner it’s not freezing.
and plugged so no oil can leak into the furnace. Separate Some freezing is due to us engineers, I’ll admit.
ignitor gas supplies should also be isolated and checked. I recall one installation where the engineer designed
The ash pits, bunkers and furnaces of coal and louvers for combustion air in the wall of a boiler room
solid fuel fired boilers should be checked for accumula- where the air drawn in traveled right over the chiller;
tion of anything that could create problems including since it was inside the boiler room it was supposed to
water, trash, rodents and sleeping contractor employees. be warm and plant personnel failed to drain it. At the
Speaking of contractors, an idle boiler should be covered beginning of the cooling season they got an expensive
to prevent damage from contractor operations above surprise. Remember that story because you can’t forget
and around it and panels and fan inlets should be sealed that standing water in the boiler plant can freeze if cold
to keep construction dust from entering them. air is drawn over it, including water in idle boilers.
I like to leave power on a burner management Your water supply piping is susceptible to freezing