Attack of the 20-foot Maintenance Man!
Now it may be of some surprise to designers and engineers that HVAC rooftop equipment needs to be serviced, so I have come up with the solution: genetically-enhanced maintenance people that are 20 feet high. Alright, so my solution has some flaws, like door handles being broken off the AC units by those giant hands, but seriously now, why such a drastic idea. Two reasons and both reared their ugly heads recently on my projects, namely roof and equipment access.
Let’s talk about roof access first. I know it’s not the engineer’s job to specify and layout roof access, but it should be at least reviewed by them. Try to put yourself in the shoes of the maintenance staff when they go to service the equipment or when something goes wrong. Typically this does not happen on a nice sunny Tuesday afternoon, it will usually occur in the middle of the night in a downpour or a blizzard. And to add insult to injury, work has to be performed in those conditions on roofs that are made from that white, plastic, slicker-than-a-greased-pig roofing material. All these conditions can quickly turn a simple situation into a worker’s compensation claim, with the maintenance or repair still left undone.
ACTION ITEM #1: In design, check all roof surfaces that have roof drains or HVAC equipment and make sure that you can reach all areas without carrying a ladder around. Remember even a three foot elevation change can be dangerous in some weather conditions. This check can be effectively done by checking the architectural roof plan and making sure that they have permanent ladders noted where you would require them. Also, in addition to checking for changes in elevation look for access to the roof itself. Man-doors are preferred, but a hatch and a ladder also work.
Second is the HVAC equipment access. In the age of high-efficiency systems, I have seen my fair share of the heat-wheel type energy recovery units; these are my number one access offenders. These AC units can be as tall as a double-decker bus, with a fan, motor, filters and possibly other components located on the top deck, and all of which require maintenance. Add in that white roof and the inclement weather and your recipe for disaster shows up again!
ACTION ITEM #2: Also in design, check the height on the rooftop HVAC air-handlers (cooling towers, chillers and anything else for that matter). If they require a ladder for proper service then consider adding a permanent catwalk system. If that isn’t possible because of budget reasons, try to get good walk-way pads all around the unit that aren’t slippery and add some permanent ladder tie-off points to the equipment casing. Other ideas may include removable or moveable scaffolding, but a lot depends on what can be easily moved to the roof and the available storage. I would also check out what OSHA has to say about this as part of your due diligence.
These simple things are easy enough to gloss over in your efforts to get you designs out the door but if you want your design to stand the test of time, with consistently low energy consumption, it has to be maintained and for that to happen you have to make it easy for the people working on you equipment to properly access to it.