US: Guidelines for a proper boiler room

With winter upon us, BioTherm has published a blog article about how growers can implement the proper boiler room in their greenhouse, including a handy checklist.

One thing to make clear right away in a discussion of what constitutes a boiler room, BioTherm's Jim Rearden writes, is to be very clear about what a boiler room is not.
  • A boiler room is not a place to store overflow supply items like pots and flats or growing media.
  • Chemicals or fertilizers should never be kept near boilers as their dust could be pulled into combustion chambers and cause serious damage.
  • It’s not a proper place to park equipment like sprayers or injectors.
  • It’s not a good place for tool storage or a workshop, as these areas tend to generate dust and debris which clog up and damage boilers.
  • Although the boiler room can also be called the “mechanical room” and include items like air compressors and back-up generators, it’s preferable to partition these items into their own optimized space.

Elements of a “Proper” boiler room

Use the following as a checklist (or just inspiration) to create the ideal boiler room for your facility. They are all important and in no certain order.

  • The boiler room can be either a separate structure or integrated into the greenhouse facility. In either case, it should be reasonably centrally located to the greenhouse facility or its contemplated future expansion areas.
  • Codes. The room or structure should comply with all local fire, structural, electrical, and construction codes.
  • Easy Access. Plan to have easy access with adequate space on roads, paths, or lanes to move large equipment to and from the boiler room. Install doors that open wide and tall enough to accommodate removing, replacing, or adding equipment.
  • Utilities. All services and utilities must be brought to the boiler room, engineered and sized for the most expansion you envision. Paying to have a proper gas, electric, or water line installed now will be a great investment for the future.
  • Combustion air - Boilers use a lot of fresh air in the combustion process (approximately 250 cubic feet per hour per 1 million BTUH of boiler input) and the boiler room needs to be set up to provide this in an adequate and controlled way. There are three ways to provide it: free air into the room, ducted air into the room, and ducted air to the boiler. The first two methods essentially “dump” outside air into the room and the last one feeds it directly to the boiler. However, “direct air” systems are relatively new and are not available on all boilers. Combustion air is a bigger issue than this space allows for coverage in extreme detail, but typically, motorized louvers are installed in an exterior wall of the boiler room to provide combustion and ventilation air in a ratio of 1 square inch per 1,000 BTUH boiler input for “atmospheric” units to 1 square inch per 4,000 to 8,000 BTUH boiler input for “power” burner equipped boilers.
  • Heating – yes, heating. It’s important that you never let your boiler room freeze, and with some of the newer higher efficiency boilers, they may not give off enough “jacket heat” to warm the room. Plan for a simple unit heater (at minimum) to take care of this.
  • Cooling – Some boiler rooms get brutally hot from the aforementioned “ jacket heat”. A properly sized fan to move this heat from the boiler room to another area that can benefit makes sense and makes working in the boiler room bearable.
  • Lighting – plan bright and adequate lighting as you would an office or any other workspace. This will help everyone do a better job during installation through operation and maintenance. No one enjoys working with a flashlight in one hand and a screwdriver in the other.
  • Floor – A concrete floor with a minimum of a broom finish should be poured. The floor needs to be engineered to handle the loading of sometimes very heavy boilers. Also, the best boiler rooms I’ve seen include “housekeeping pads” for each floor-mounted piece of equipment. This is essentially a small slab poured on-top of the floor in the dimension of the equipment to be installed. Usually formed simply with 2”x4”’s, the housekeeping pad makes it easy to keep the boiler room floor clean.
  • Drains – the proper boiler room plan includes an engineered floor drain system with strategically placed grated inlets to accommodate water from pressure relief valves, drain or blow-down valves, condensate water from flue-gas condensing boilers (check environmental regs about this one), and floor hose down clean-up run-off. It’s vital that the floor drain system be integrated with the boiler system drain points before you start construction of the boiler room.
  • Computer controls – While planning the layout of the electrical panels in the boiler room, remember to include space for any computer control panels that need to be located there as well. More boiler systems are being operated via the central environment control system these days and since these are the brains of the operation, it’s smart to locate them strategically in a easy-access, well-lit space.
  • Fire Safety – Depending on local code, you may need to have an automatic sprinkler system installed in your new boiler room. At minimum though, plan on a good quality fire extinguisher.
  • Penetrations – The typical boiler room has vents, like chimneys or “breaching” going out the top and heating water pipes going in and out of the side walls. Plan ahead where these penetrations will be made and follow proper procedures to seal them up. Depending on the style of construction, your roof may require “roof curbs” around the roof vents. Code may require that wall penetrations have a “fire-stop” or special sealant for safety wherever they go. If you have air inlets on the side walls, make sure they are above snow levels.
  • Venting – When boilers burn hydrocarbon fuels like oil, natural gas, or propane, they release exhaust in what is called the “products of combustion”. One of the byproducts is water vapor and depending on the fuel type, it will contain several other elements that give it an acidity comparable to vinegar. Unless your boiler system is a “condensing” type or equipped with a flue gas condenser, this corrosive exhaust needs to be quickly carried up and out of the boiler room through an engineered venting system. A proper venting system is design to removes the “exhaust steam” fast before it can cool down enough to form condensation droplets which can ruin expensive equipment in a short time. Usually, the venting system is a metal duct that needs to terminate well above the boiler room and any surrounding buildings or obstacles. Depending on the height necessary, the venting may require an engineered “guy-wire” system to support it and will terminate with a “wind-proof” cap. Planning ahead here will make life much easier. I’ve seen many instances of trusses or other framing in the way of the venting. Make sure your construction plan includes clearances for the vents.
  • Central Document Storage and Maintenance Schedule – Set aside an area to keep a log-book and to file all maintenance records. Also, a binder should be created to collect and store all product sheets, instruction manuals, and system drawings. The payoff to keeping this information organized comes back many times in reduced frustration over the years. In this same area, I like to see a wall-mounted and laminated sheet with all service intervals planned for the next 20 years or more. Hang a grease pencil nearby to record the work for a quick visual reminder. Doing annual maintenance seems to be a struggle for almost all growers….how about putting your boilers on the same birthday party roster you set up for your staff? This most vigilant team member may not enjoy cake and punch, but an annual cleaning and adjusting will certainly be appreciated! I know of a boiler service company that actually sends cards…..”Happy Birthday, ya big galoot!”.
  • Emergency Numbers and Procedures – Set up signs that readily identify the company you will turn to for service work on an annual and/or emergency basis. Also, if there special procedures (like back-up fuel switch-over) that must be done in times of emergency, make them clear and train your staff.
  • Spare Parts and Special Tools – Set up an area for spare parts that are likely to fail occasionally. Things like pump motors and ignitors seem to quit when vendors and supply houses are closed and, in most cases, growers cannot afford to wait until they open to get the heat going again. Also, keep any special tools you need to work on your boilers in this area. Some growers need to be able to switch fuels on less than a few hours notice. If you’ll need to change fuel orifices on the fly, you should keep all the parts and tools you’ll possibly need handy. It will pay to rehearse the procedure occasionally.
  • During Construction and Installation – Keep all documents and packing lists in one place. Protect all materials and equipment from weather and theft. Use “good receiving practices” when shipments arrive. Construction is hectic enough….but being organized about this phase will pay off in reduced frustration down the line. Also, boilers are not good workbenches. Even though many of them offer a convenient horizontal surface, don’t let them turn into a “catch-all”. They’ll get scratched and worn and you’ll regret it later.
  • Finishing – The proper boiler room is finished with cleanly installed pipe insulation, painting of all exposed fittings and pipes, and labels indicating pipe contents (gas, hot water supply, etc), and flow direction. Some regional codes require gas lines to be painted, usually safety yellow.
For more information:
BioTherm Inc.
476 Primero Court
Cotati, CA 94931
Phone: 707-794-9660
Fax: 707-794-9663

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