The opening date slips for the same reason almost every time. Not construction, and not equipment delivery. A commercial kitchen fit out fails on the connection schedule, meaning nobody wrote down what every single appliance needs in gas, electricity, water and drainage until the appliances were already on the floor.
Restaurants are not houses with more equipment. The rules are different, the inspections are different, and there are two or three authorities to satisfy rather than one.
What a commercial kitchen needs that a residential one does not
Four things change the whole shape of the job.
Plan review before work, not inspection after it. Drawings go to the health authority and to the building department for review before construction. Both can require changes. That review is a schedule item measured in weeks, and it happens at the front of the project rather than the back.
Indirect waste. Anything that handles food or food contact water cannot drain directly into the sanitary system. It discharges into a floor sink or a receptor with an air gap, so that a backup in the building drain cannot reach the food equipment. This single rule dictates floor drain positions, which dictates equipment positions, which dictates the layout.
Grease. Kitchen waste passes through an interceptor sized for the fixtures discharging to it. It occupies real space, indoors or outside, and it carries a cleaning obligation that somebody has to own from day one.
Backflow protection. Every connection where building water could be contaminated needs the right device. The dish machine, the coffee and espresso equipment, the ice machine, the mop sink, any hose connection.
The connection schedule is the whole project
Before drawings are finished, every piece of equipment on the floor plan needs a row in one document listing its electrical requirement including voltage and phase, its gas input if any, its water connections hot and cold, its drainage requirement and whether it is direct or indirect, and its required clearances.
Two traps live in that document and both are expensive.
Phase. Used commercial equipment is a legitimate way to fit out a kitchen and it is full of three phase machines. Many small commercial buildings have a single phase supply. Discovering that after the equipment arrives means either different equipment, a phase converter, or a service change that involves the utility and a long lead time.
Total connected load. Add the gas inputs together and check them against the meter, and add the electrical loads together and check them against the service. On a change of use, where a retail unit becomes a kitchen, both of those are almost always short, because the building was never intended for this. That is service and panel work and gas piping work, and both are lead time items rather than site decisions.
Hot water is a demand curve, not a daily total
Residential water heating is sized around a household’s rhythm. A kitchen is sized around its worst fifteen minutes.
The three compartment sink filling, a dish machine running its cycle, hand washing stations in use and prep sinks running all overlap in service. Sizing on daily consumption produces a system that runs out during dinner every night, which is the complaint, not a theory.
The dish machine also has its own requirement. High temperature machines need water delivered hotter than the rest of the kitchen, usually through a booster heater, and that booster is itself a substantial electrical load that belongs in the load calculation. Low temperature machines use chemical sanitising instead, which changes the water heating requirement and the operating routine. That choice belongs to the operator and it has to be made before the water heating is designed, not after.
The hood, and the interlock nobody quotes
The exhaust hood over the cooking line is the most consequential single item in the kitchen and it touches all three trades.
It pulls a large volume of air out of the building, and that air has to be replaced. Makeup air is not optional and it is not free: replacement air usually needs conditioning, or the kitchen is unbearable in January and the exhaust performs badly because the building is depressurised. A depressurised building also backdrafts any atmospheric appliance in it, which is a safety problem rather than a comfort one. This is mechanical work and it belongs in the design, not in the second year.
The hood’s fire suppression system then has to interlock with the appliances beneath it. When it discharges, fuel to those appliances must stop: gas via a valve that closes and stays closed until reset, electric appliances via a shunt trip. Wiring that interlock is electrical work that only exists because of a mechanical system, which is precisely the kind of scope that falls between separately hired trades and shows up as a failed inspection days before opening.
Drainage, floors and the things that are hard to change later
Floor sinks and floor drains go where the equipment needs them, which is why the equipment layout has to be settled before the slab is cut or poured. Moving a floor sink after the floor is finished is not a plumbing job, it is a floor job.
The floor finish itself has to tolerate water, grease and cleaning chemistry, and it has to be coved at the walls in most jurisdictions so there is no crevice at the junction.
Grease bearing waste routes to the interceptor and non grease waste, such as toilets, generally does not, which means two drainage paths rather than one. Getting that wrong means either an undersized interceptor doing work it was not sized for, or sanitary waste passing through it, and neither is a cheap correction. Drain services should be involved while the layout is still on paper.
Inspections, and there are more of them
Expect plumbing, electrical and mechanical inspections as on any project, plus fire inspection of the suppression system and its interlock, plus a health inspection before opening.
They are not independent. The fire inspection depends on electrical and gas work being complete and correct. The health inspection depends on plumbing and finishes. A failure anywhere in that chain moves the opening date, and the opening date is usually attached to a lease payment that does not move.
The practical consequence is that the trades have to finish in a coordinated order, with somebody holding the whole sequence. On a residential job that is a convenience. On a fit out with a lease running, it is the project.
What a good scope document contains
It should include the equipment connection schedule, complete, with a row for every appliance. It should state the total connected gas load against the meter capacity and the total electrical load against the service, with the shortfall named if there is one. It should mark every floor sink and floor drain on the layout. It should state the interceptor size and where it sits, and who cleans it. It should name each backflow device by application. It should state the hot water design and whether the dish machine is high or low temperature. It should describe the makeup air arrangement and whether it is conditioned. It should say who wires the hood interlock and who tests it. And it should list the inspections in order with the dependencies marked.
If you have a fit out in the Columbus area and want that scoped in one pass, start at the contact page and say all three trades are in scope.
Frequently asked questions
Why does my commercial kitchen equipment need indirect waste?
Because a blockage in the building drain must never be able to reach equipment that handles food or food contact water. Indirect waste means the appliance discharges into a floor sink or receptor with an air gap, so there is a physical break between the appliance and the sanitary system. It is a public health rule rather than a plumbing preference, and it drives the layout, because floor sink positions determine where equipment can go.
Do I need a grease interceptor?
Almost certainly, and the size and type are set by the local authority based on the fixtures discharging to it, so this is a question for plan review rather than a general answer. What matters commercially is that the interceptor occupies real space, indoor or outdoor, and that it carries an ongoing cleaning obligation. Decide early who owns that obligation, because an interceptor that is never serviced stops working and becomes an enforcement problem.
Can my building supply three phase equipment?
Check before you buy, especially if you are buying used equipment, because a lot of commercial kitchen machinery is three phase and many small commercial buildings have only single phase service. Discovering this after delivery leaves three options, all bad: different equipment, a phase converter, or a service change that involves the utility and a long lead time. The connection schedule exists to catch exactly this.
Why does a kitchen hood need makeup air?
Because a hood removes a large volume of air from the building and that air has to come from somewhere. Without a designed makeup air supply the building goes negative, which means the hood underperforms, doors become hard to open, the space is cold in winter, and any atmospheric appliance in the building can backdraft. Makeup air usually needs conditioning to be usable in an Ohio January, and that is a design decision rather than an add on.
What is the hood fire suppression interlock?
It is the wiring and valving that stops fuel to the cooking appliances the moment the suppression system discharges. Gas is shut by a valve that closes and stays closed until manually reset, and electric appliances are dropped by a shunt trip. It is electrical work that exists only because of a mechanical system, which is why it falls between separately hired trades so often, and it is a fire inspection item. Establish who is wiring it and who is testing it at the start rather than in the last week before opening.