Steel thickness: lockers tend to be made from a standard thickness of steel, which is commonly 0.8 mm. thick; but heavy-duty or high-security lockers are offered as a standard option by some manufacturers, or may be available on special order. A typical locker of this sort may be constructed from steel 1.2 mm. thick, for example, and is usually fitted with three-point locking, regardless of the number of tiers.
Don't count on finding this kind of thing. Some silly people put bombs in there. Our Homeland Security people try to head those things off. In Europe, especially GB, you can't even find a trash can on the sidewalks for the same reason. A worker at the train station told us to just throw it on the floor, the people in the green jackets will pick it up. Really. What a world we live in.
Number of locking points: Locker doors may lock with either single- or three-point locking, but this is not normally chosen as a separate option, and the choice is usually dependent on the number of tiers in the lockers, or whether they are a high-security model, although some manufacturers do allow purchasers to specifically choose an option here that goes against their normal practice. Single-point locking locks the door at only the point where the latch engages with the door-frame, whereas three-point locking uses extensible steel rods to lock the top and bottom of the door as well.
Terry, there are many storage unit places closer to the airport, but then of course you'd have to rent a car. DIA Self Storage, for example, is less than 10 miles away. You can google map Denver International Airport, then "search nearby" for "self storage units" if you think that's something you might want to do. http://www.coloradoselfstorage.com/
Conveniently located across the street from Denver Union Station, LUGDEN mobile bag check provides hourly, daily, overnight, and weekly luggage storage for Denver visitors on a layover from Denver International Airport, waiting to check-in to an Airbnb or downtown Denver hotel, attending the Rockies game at Coors field, and anyone wanting to enjoy their time in Denver sightseeing, shopping, dining and exploring, baggage free. Flat rate for all bags: suitcases, backpacks, purses, duffel bags, skis, snowboards, golf clubs, pelican cases, etc. Reservations are recommended for fastest check-in, but walk-ups are always welcome. After hours service is available by appointment. Visit our website for more information or to book a reservation.
There are two safes in the RPD--one in the West Office and the other in the Waiting Room. Both yield valuable resources well worth grabbing. We won't spoil what's inside each here (spoiler: they're all useful items), but we will reveal how to open them. The safe solutions are found in memos scattered around the building, which we've detailed the locations of for all of you completionists out there.