The dock side
Loading Dock Personnel Door Service in Charlotte, NC
Tell us what the dock door is doing and what has hit it. Call (984) 253-8579.
Steel door spec lookup
Maps the duty an opening actually sees to the performance levels and face-sheet gauges of ANSI/SDI A250.8 and the tested endurance levels of ANSI/SDI A250.4.
Choose an application; the full lookup table below is the entire rule set.
| A250.8 level | Face sheet | Typical duty | A250.4 endurance |
|---|---|---|---|
| Level 1 — Standard duty | 20 gauge | Interior, light traffic | Level C — 250,000 cycles |
| Level 2 — Heavy duty | 18 gauge | Corridors, moderate traffic | Level B — 500,000 cycles |
| Level 3 — Extra heavy duty | 16 gauge | Hard-used interior, exterior service | Level A — 1,000,000 cycles |
| Level 4 — Maximum duty | 14 gauge | Docks and hard-use exterior | Level A — 1,000,000 cycles |
A great many dock personnel doors were value-engineered in at Level 1 or 2 and have been failing ever since. When one has failed twice, putting the same level back is a decision worth making deliberately rather than by default. Exterior steel should be specified galvannealed (zinc-iron alloy coated, per ASTM A653) rather than plain galvanised where paint has to stay on it.
The busiest door on an industrial building is the small one
Every dock has an overhead door that gets the attention and the budget. Beside it there is a single hollow metal leaf that people actually walk through — every driver, every receiving hand, every smoke break, every delivery that did not need the big door open. That leaf sees more cycles in a week than the overhead door sees in a quarter, and it is the one nobody has a maintenance line item for.
It also sits in the worst environment on the site. Weather at the threshold, salt and grit tracked across it, carts hitting the bottom rail, pallet corners catching the frame, and a habit of being propped open with whatever is nearest because somebody is carrying something.
Sectional and coiling doors are a separate trade with separate tooling and separate risk, and this outfit does not work on them. The personnel door is the whole lane here.
Dock and service entrance work we take on
Hollow metal and aluminum personnel doors at docks, service entrances, yards and back corridors. The work skews toward frame and leaf condition rather than hardware, which is the reverse of most of this site.
Corrosion at the bottom rail and the frame's feet
The classic dock door failure. Water sits at the threshold, the bottom of the leaf and the base of the frame go first, and by the time it is visible the section carrying the hinge or strike load may already be compromised. Whether it is repairable depends on how far up it has travelled, and the honest answer is sometimes that it has not been a repair for a while.
Galvannealed versus galvanised, and why the paint keeps failing
Exterior steel doors should be specified with a zinc-iron alloy coating rather than a plain galvanised one, because galvanised coatings — particularly the heavier weights — are known to give trouble with paint adhesion and welding. A dock door whose paint keeps lifting in sheets frequently has the wrong coating under it, and repainting it again will not fix that.
Frame anchors that have let go in the wall
A frame in masonry or a block wall relies on its anchors, and when they fail the frame moves under load every time the door is used. The symptom presents as a latching or dragging complaint and gets treated as a hardware problem for years. A frame that visibly flexes when the door is pulled is not a strike adjustment.
Impact damage from carts, jacks and forklifts
Denting on a steel leaf is repairable within limits — shallow dents can often be filled per the manufacturer's listing, typically under an eighth of an inch deep, but holes through the face sheet are not fillable and want listed repair material or a new leaf. On a labelled assembly the limits are stricter and the label decides, not the technician.
Wrong performance level for the traffic
ANSI/SDI A250.8 sorts standard steel doors into levels with face-sheet gauges attached, running from 20 gauge at Level 1 to 14 gauge at Level 4. A great many dock personnel doors were value-engineered in at Level 1 or 2 and have been failing ever since. Separately, ANSI/SDI A250.4 grades endurance at 250,000, 500,000 and a million cycles for levels C, B and A. Putting the same light leaf back in is a decision worth making deliberately rather than by default.
Kick plates, edge guards and armour that should have been there
Unglamorous, low in cost, and the difference between a leaf that lasts and one that gets replaced twice. Fitting protection after a repair is usually the highest-return part of a dock door job.
Hardware chosen for the environment rather than the catalogue
Exterior dock hardware wants to tolerate grit and washdown. Closers get sized against a real wind exposure. Where the door is in a means of egress, exit hardware still has to work at the operating forces the code sets for egress doors — thirty pounds to set it in motion and fifteen to swing it fully open — and a stiff, gritty dock door frequently does not.
What moves a dock door figure
| What we find | Where it lands |
|---|---|
| Hardware only, frame and leaf sound | A visit, usually inside a morning. |
| Leaf damaged, frame sound | A leaf, ordered against the existing frame's throat and prep. Lead time depends entirely on whether it is a stock size and whether it needs a label. |
| Frame anchors failed or frame corroded at the base | The larger job. The frame comes out or gets sub-framed, and the wall construction decides which. |
Which of these three it is can usually be narrowed on the phone, and it is worth doing because the middle one has a lead time attached.
How dock openings get treated
The frame gets checked before the hardware
On dock openings the frame is the usual culprit and the hardware is the usual scapegoat.
Repair limits get stated rather than stretched
There is a point past which filling a dented leaf stops being a repair, and on a labelled assembly that point is set by the listing rather than by what looks acceptable.
The right leaf gets specified, not the same leaf
If the door has failed twice, putting the same performance level back is a choice, and it should be a conscious one.
Overhead doors are not touched
Said plainly so a receiving manager does not book us expecting a coiling door repair.
How a dock door call runs
- 1. What hit it, or did nothing hit it
Impact damage and slow deterioration are different jobs and the caller usually knows which.
- 2. Does the frame move
Pull the door hard and watch the frame. If it flexes, that is the job, and it changes what goes in the van.
- 3. Read the bottom eight inches
Of both the leaf and the frame. That is where dock doors die and it is where the honest scope gets set.
- 4. Fix, or scope the leaf or frame properly
Including the label question, because a rated assembly narrows the options considerably.
- 5. Add the protection that should have been there
Kick plates, edge guards, a threshold that actually sheds water. Trivial to add while the opening is already apart, and a real expense to retrofit later.