Labelled assemblies
Stairwell and Cross-Corridor Door Service in Charlotte, NC
Say what the door is doing and whether it carries a label. Call (984) 253-8579.
Clearance gauge
Checks measured gaps at the head, jambs, meeting stiles and undercut against the clearance limits NFPA 80 publishes for hollow metal fire door assemblies.
Enter what you measured; the limits applied are printed in full below.
| Location | Published limit | As a decimal range |
|---|---|---|
| Head, jambs and meeting stiles | 1/8 in, with 1/16 in tolerance either way | 0.0625–0.1875 in |
| Undercut, bottom of leaf to finished floor | 3/4 in maximum | up to 0.75 in |
Twenty-minute doors in hollow metal frames are allowed slightly more room; the door's own listing governs. New floor covering reduces the undercut and is the most common way a compliant door goes out of tolerance without anyone touching it. This is not an inspection record. The annual record NFPA 80 asks a building owner to keep comes from an inspector whose qualification your authority having jurisdiction accepts; what this gauge tells you is whether that visit is likely to go badly.
These doors only have to work on the worst day, which is why nobody notices they stopped
A stair door that closes but does not latch looks completely fine. It swings, it shuts, the corridor looks tidy. It is also not doing the one job it exists for, and the day it matters is not a day anybody gets to test it first.
Cross-corridor pairs are worse, because they have more to get wrong. Two leaves, a coordinator making sure they close in the right order, sometimes an astragal, often a hold-open device wired to the fire alarm, and a set of clearance tolerances that are far tighter than anybody expects until they have watched an inspector with a feeler gauge.
Stair and corridor work we take on
Service, adjustment and hardware replacement on labelled and unlabelled stair, corridor and cross-corridor openings. What this is not: certified annual fire door inspection with a documented record. We will tell you what would fail and why, and the record itself should come from an inspector your authority having jurisdiction accepts.
Self-closing and positive latching
The two behaviours the whole assembly exists to deliver. A door tested from a half-open release rather than from wide open is the useful test, because that is the condition most real closings happen in and it is where undersized or worn closers give up.
Clearances at head, jambs and meeting stiles
NFPA 80 runs tight here — on hollow metal assemblies the clearance at the head, jambs and meeting stiles sits at an eighth of an inch with a sixteenth of tolerance, and twenty-minute doors in hollow metal frames are allowed a little more. Undercut is capped at three quarters of an inch to the finished floor. Non-compliant clearances are among the most commonly recorded deficiencies anywhere.
Coordinators and astragals on pairs
A coordinator makes the inactive leaf close first so the astragal does not foul the active one. When it wears or gets bent, the pair closes in the wrong order, the active leaf bounces and does not latch, and the usual response is to adjust the closers harder — which makes the doors unusable while not fixing the actual fault.
Getting rid of the wedge properly
A corridor pair that spends its day propped open is not a discipline failure, it is a building telling you the doors are in the way of how people actually move. Kicking the wedge out and writing it up achieves nothing; it reappears by Monday. What works is listed hold-open hardware wired into the alarm system, which lets the pair sit open through the working day and drop shut when the panel calls for it. The alarm contractor owns their half of that interface and we own ours, and both halves have to be arranged before either is worth starting.
Opening force where accessibility applies
The 2010 ADA Standards put a five pound ceiling on interior hinged openings, and set a floor of five seconds on the sweep from ninety degrees down to twelve degrees off the latch. Rated leaves answer instead to the authority having jurisdiction. Persuading a labelled door to latch every time while still opening under that ceiling is real tuning work, and it is rarely one turn of one valve.
What sets the scope on a labelled opening
| Condition | What it usually means |
|---|---|
| Closer worn or wrongly adjusted | Adjustment or a replacement closer. The smallest version of this job. |
| Coordinator bent or seized on a pair | A part, and a re-tune of both leaves afterwards. |
| Clearances out of tolerance | Depends which way. Too much gap can sometimes be addressed with listed accessories; too little usually means the leaf or frame has moved. |
| Label missing, painted over or unreadable | Not a repair at all. It is a documentation problem and it needs resolving before anyone modifies the assembly. |
| Field modification already done to the leaf | The hardest conversation on this page. A hole cut in a labelled leaf is not something a repair puts back. |
Nothing on a labelled assembly gets a figure before somebody has read the label and the clearances.
The ground rules on labelled assemblies
Latching is tested the way doors actually close
From half open, repeatedly, not once from wide open with a helpful push.
Pairs are treated as one assembly
Closers, coordinator, astragal and both leaves get tuned together or the fault comes back.
The label sets the limits
What can be done to a rated leaf is decided by its listing, and no part goes on that is not permitted for a fire door assembly.
Wedges get replaced with something legitimate
Rather than removed and reported, which achieves nothing except that the wedge comes back on Monday.
Inspection certification is named as out of scope
We service the doors and we say what would fail. We do not issue the record.
How a stair or corridor call runs
- 1. Label first
Hinge edge of the leaf, rabbet of the frame. Present or absent changes every subsequent decision on the opening.
- 2. Watch it close from half open
Several times. Most latching faults declare themselves in the first two minutes if you stop helping the door.
- 3. Measure, tune, and re-test under the real condition
Clearances checked, closer sweep and latch speeds set, coordinator sequence verified on pairs, and the whole thing run again before anybody signs off.