Commercial doors range from high-end decorative entry doors equipped with automatic door operators to alley or loading dock doors that get opened using a cart, fork lift or pallet jack. Using these two examples, we show how the operational life of a door, opening and the attached hardware can be dramatically different.
In addition to the doors, the condition of the building is also a significant factor in the operational life and a good indicator of the problems that may occur. By building condition, we are referring to its structural integrality in regards to the door openings. They should be plumb, with solid jambs and doors that swing open and closed and latch without external resistance.
Poor construction can result in problems with door operation and air infiltration. With today’s poured concrete buildings, solving a problem can be costly and time consuming.
The placement of exterior doors plays a significant role in potential problems. For example, take an exterior hollow metal door located on the east facing side of a poured concrete building. There was no awning or cover structure over this door because it was a secondary entrance. To make matters worse, the slab-sided building and the door were painted a dark color that absorbs heat. At peak summer temperatures, the hollow metal door became so hot that it warped. Over time, the heat warpage had a residual affect and the door became permanently bowed along the lock edge. The door had to be replaced as people could no longer either open or close the door.
Door warpage as a result of heat is basically limited to hollow metal doors. In many instances, if the door becomes warped, it may return somewhat to shape when pressure is no longer exerted or when the temperature cools off. However, most warped doors will stay warped or get worse.
Note: In the early stages of warping, you must check for this problem during the hottest part of the day.
Door manufacturers offer doors that are designed to resist warpage. As an example, Steelcraft B-Series flush doors have steel stiffened core construction with welded 22 gauge hat section stiffeners and epoxy filled mechanical interlock edges provide structural support.
The amount of traffic through the door has an affect on the operational life. High traffic increases amount of wear on the door, jamb, hinges, locks, closers, etc. In addition to the amount of traffic, the age group of those who operate the doors must also be considered. Teenagers are probably the toughest age group on doors and openings. Additional considerations should be made if the openings located at a middle or high school.
Door traffic is usually divided into three categories: high, average and low. According to Rixson, a provider of concealed closers, pivots and door holders, a large department store frequency of door openings can be 5,000 per day or 1,500,000 per year. High frequency usually begins at 400-500 openings a day. Average traffic frequency can be a school corridor door having a frequency of 80 openings per day or 15,000 per year. A residential bathroom door has a low frequency of 25 openings per day or 9,000 openings per year.
For high traffic areas, the opening and doors should be equipped with Grade 1 or heavy duty products to help extend the operational life of the door and jamb. I can never understand why a large office building will have Grade 3 cylindrical locks installed onto the common restroom doors.
Pivots & Hinges
Another consideration is the pivots and hinges. Code requirements determine the size and materials for hinges. For example, the National Fire Protection Association (NFPA) 80 Handbook sets minimum quantity, size and weight (thickness) for swinging fire doors. It also stipulates non-spring hinges must be the ball bearing type.
Hardware industry standards call for two butt hinges for doors up to 60 inches in height. An additional butt hinge is required for each additional 30 inches or fraction of in height. For example, a 92- inch door will have four hinges. The fourth hinge is required for the two inches over the 90-inch height.