Denver's club capacities - and rules for how many people can be in a club - vary by size.
Denver firefighters say a number of things are important for safety, including a number of exits so people can get out if something happens.
Denver Division Fire Chief Joseph Gonzales says most clubs have sprinkler systems installed. The department also performs random inspections on a regular basis.
He says if you are with someone else, always make a plan on where to meet outside if trouble comes up.
If you ever feel like the place you're in is overcrowded or against code, notify the management or the fire department.