Rolling Steel Fire Door Guide

A rolling steel fire door looks like any other coiling door until something goes wrong. What makes it a fire door is a label, and what makes that label mean anything is a release mechanism that closes the door without power, without a person, and at a speed that won’t injure anyone standing underneath. This guide covers how those mechanisms work, what they must have, and how they’re tested.

1. What makes it a fire door

Three things, and all three have to be present. A fire door carries a label identifying it as a tested assembly for a stated rating. It is self-closing and stays closed once released. And it is installed in the opening with its hardware intact, because the rating belongs to the whole assembly: door, guides, hardware, release device and frame.

That last point is where most compliance problems live. A technician who removes a fusible link housing because it caught on a pallet, or who wedges a door open for airflow, hasn’t caused a maintenance issue. They’ve defeated the fire separation, and the door no longer performs the function it was installed for.

2. Two release families

Every automatic closing system has to do the same thing: stop holding the door up. There are two ways to arrange that, and knowing which one you’re looking at decides how a drop test is performed and what resetting involves.

On a push-up fire door in the charged position, a dropout arm is held engaged by a sash chain or cable. A fusible link joins two sections of that chain. When the link melts, the chain separates, the drop arm releases, and part of the spring tension goes with it so the door falls closed under control.

3. Fusible links and where they go

A fusible link is two metal pieces held together by solder that melts at a set temperature, typically around 165°F for most fire door applications. It is simple, needs no power, and works when everything else has failed. That’s also why its placement matters so much: a link that sits in dead air above a false ceiling will never see the heat it’s meant to respond to.

• Height. 4 to 12 inches below the ceiling, so the link sits in the hot gas layer that forms at the top of a room, not at head height.
• Both sides. Coil side and opposite side, because heat does not reliably reach one elevation only.
• Near the opening. Additionally required on the coil side, so a fire at the opening releases the door early rather than after the room is fully involved.
• Housing. Where a drop or false ceiling exists above the opening, the link needs a housing that keeps it exposed to the heat it’s meant to detect.

Reading and choosing a fusible link

A link carries its specification stamped on it: the manufacturer, the listing mark, the temperature rating, a pull rating and a date. Those markings are what an inspector reads, so a link with the stamp worn or painted off is already a finding.

• Heat environment. A 165°F link has a recommended maximum exposure of 100°F. If the opening regularly runs hotter than that, step up to 212°F, otherwise the link can let go on a hot day.
• Sprinklers. The link rating must be lower than the temperature rating of the sprinkler heads, and the link should be shielded from the head so it is not drenched.
• FM-listed doors need FM links. Factory Mutual links differ from UL links. Fitting the wrong type on an FM-listed door can fail an inspection, stop the AHJ or FM inspector approving it, and void the FM rating.
• Creep. A link under constant load slowly fractures (“cold flow”). It is why some manufacturers say to replace annually. NFPA 80 does not set a replacement interval, but it does require installation to the manufacturer’s instructions.

Links connect to the sash chain or cable with S-hooks and should sit at least 6 inches from any fixed point, such as a pulley, eyebolt or through-wall pipe, so they do not catch when they release. Where a drop or false ceiling hides the opening, the link needs a housing. All of the links on a door are interconnected, so separation of any one of them closes it.

Sash chain and cable: the quiet failure

Twisted or snagged chain and cable is one of the most commonly reported reasons a conventional fire door does not close. The release only works if the chain runs free through every pulley, through-wall pipe and eyebolt when the link lets go.

• Use chain and cable supplied by the original fire door manufacturer.
• Plastic-coated wire rope should not be used.
• Cable should be a nominal 1/8 inch or 3/32 inch diameter.
• Avoid angles under 90 degrees, and keep the link’s travel path away from eyehooks, wall penetrations and obstructions.
• Put turnbuckles above a height where they can be tampered with.

The AHJ has final approval of the link location and routing, so a layout that looks neat to the installer can still be rejected on inspection.

4. Electrical release devices

Where a door is tied to a fire alarm rather than relying only on heat at the door, a release holder takes the electrical signal from the panel, a smoke detector or a heat detector and converts it into a mechanical release. The same mechanism then runs: cable or chain releases, the door closes under the governor.

The critical requirement is the power supply. A release holder needs a standby source, or the door must drop on any power outage. A release device that holds a door open through a blackout is holding a fire door open during a fire, and that is precisely the failure nobody plans for.

Four kinds of electro-mechanical release

Electrical release devices come in several configurations. The differences matter because they decide what happens when the alarm sounds, when the power fails, and when something is in the way.

Two features are worth knowing about. The release can delay for up to 10 seconds after the signal (verify local code), which cuts nuisance drops from alarm blips and, more importantly, gives people and equipment near the door time to notice what is happening. And the obstruction logic reverses a blocked door, retries up to three times, and then either closes onto the obstruction or releases and rests on it. That final behaviour is selectable in the unit and is a decision for the AHJ.

Detectors that trigger the door

Where a door is tied to the fire alarm instead of relying only on heat at the opening, the detector and the release device have to be compatible. They must use Form C contacts, and where there are several detectors they are wired so that any one of them closes the door.

• Photoelectric detectors measure light scattered by smoke. They can be fooled by theatrical effects or by areas that regularly see dense smoke.
• Ionization detectors measure visible and invisible combustion particles. Vehicle exhaust and chemical vapours can trip them. Combined smoke and heat models exist.
• Heat, rate-of-rise and CO₂ detectors are available and can work alongside smoke detectors.
• End-of-line relays are required by UL at the end of every smoke detector circuit. If power to the detectors is lost, the relay flips the circuit to alarm, so the door closes. Without it a dead detector looks exactly like a healthy one.

Detectors or links go on both sides of the wall, interconnected, except that detectors are not required on the exterior side of an exterior wall. Mounting is set by NFPA 80 and NFPA 72, and always by the manufacturer’s instructions first. Smoke detectors usually give no warning when they trip, so strobes, horns or voice annunciators are recommended where nothing else warns people, or where pedestrians and moving machinery are close to the door.

Detector wiring also decides how many doors drop. Tying detectors into the whole building alarm can drop every fire door at once, while grouping doors into local zones means only the doors in the affected zone close.

5. The governor and closing speed

Once the door is released it falls, and an ungoverned falling door is a hazard rather than a safety device. The governor limits the descent to somewhere between 6 and 24 inches per second depending on the door and design.

On some systems the operator itself acts as the governor, which gives finer control over the closing rate. Either way, the test is the same: the door has to travel at a speed that won’t injure a person in the opening, and it has to reach the floor and stay closed.

NFPA 80 states it directly: the closing speed must average no slower than 6 inches per second and no faster than 24. Fire rated doors from every manufacturer are designed to meet that, and the installer has to test the installation to demonstrate it for the AHJ. Note that this is a different figure from a motor operator’s normal running speed, which is typically 6 to 12 inches per second.

6. Inspection and drop testing

A drop test answers one question: if the release were triggered right now, would this door close fully, at a controlled speed, and stay closed? Nothing else proves it. A door can be balanced, quiet and serviceable and still fail to close because a link is painted over, a chain is seized, or a disconnect was never reset.

What a certified test involves

The sequence below is what a qualified technician performs, and what you should expect to see if you are present. It is here so you can tell a thorough visit from a quick one.

Step 1: visual inspection

The whole assembly is checked before anything moves. This is where most problems are found, and finding them here is cheaper and safer than finding them during a drop.

Step 2: operational inspection

The door is run through a complete cycle to confirm it moves smoothly. Signs of a broken spring are excessive lift effort, excessive hoist effort, or a struggling operator. Any abnormal noise or damage is investigated and repaired before anything is dropped.

Step 3: the drop test

The drop is only performed once both inspections have passed and the door is believed free of defects. On the day, expect the technician to do the following, and expect to be asked for a witness:

How drop speed is measured

Ask for the number. A measured speed in that range, written on the report, tells you the governor and counterbalance are doing their jobs. “Tested and passed” with no figure is not the same thing.

Every means of activation gets tested

NFPA 80 requires testing by all means of activation, repeating the drop as needed so every release device and location is proven. A door that drops from its floor-level disconnect has not necessarily been proven to drop from its alarm signal, and an alarm-path failure is the one that matters in a real fire.

The paperwork to ask for

Most new doors ship with a drop test form, and manufacturers supply them. It is completed whenever a drop test or inspection is performed, and it is kept on record for AHJ inspection for three years. One copy stays with the door, one with the installer or dealer, and one with you. Keep your copy somewhere you can find it when an inspector or insurer asks, not in the maintenance van.

When a door should be replaced rather than tested

Not every door should be serviced, and a reputable company will tell you so. The industry guidance (DASMA TDS 257 and 275) sets out the situations where testing and servicing should be declined altogether. If a contractor agrees to test a door in the first three rows below, that is a warning sign about the contractor.

Repairs are made and defects corrected without delay, with parts from the original manufacturer. Labeled retrofit options may exist for the operator and automatic closing device if the AHJ approves, and a retrofit operator may come from another manufacturer if it is listed. Field modifications must be approved by the listing agency, the manufacturer and the AHJ, and a field inspection may be required. Every repaired fire door is drop tested, at least twice, and a written record is kept including the witnesses.

Bottom bars have a special provision worth knowing about, because it is a common shortcut. A replacement must come from the original manufacturer under the listing agency’s follow-up service procedure: the original label goes back to the manufacturer, who supplies a new bottom bar with a new label. A bottom bar fitted from stock, with no label, has broken the certification of the door.

About the floor-level disconnect

Many doors have a floor-level disconnect, which allows the release to be tripped without tools or a ladder. It exists so the door can be tested more often than the annual visit, but “easier to test” is not the same as “safe for anyone to test”. The stored energy in the door does not change, and the failure mode of a mis-sequenced drop is an uncontrolled curtain.

• Treat it as a device for a trained technician, not a maintenance shortcut.
• If your insurer or AHJ expects more frequent testing than annually, schedule more frequent visits from your certified partner rather than performing them in house.
• Keep the disconnect secured against unauthorised use, and never activate it on a damaged door or while the door is moving.
• Always two drops in a row, which is a trained sequence, not a quick check.

If a drop test fails

The table below is what a technician will be looking at. It is useful in a report, and useful when you want to understand why a door was condemned, but the adjustments are technician work.

Booking the annual test

Three things make the annual visit painless: know the inventory, know the date, and know who is allowed to do the work. Ask any provider for their fire door drop testing certification before they touch a door, ask for the measured drop speed on the report, and keep the signed form for three years. If a door has been painted, altered, propped or tied off since the last visit, say so when booking, because it changes what the technician has to check.

7. Resetting after activation

After a genuine activation or a drop test, the door has to be returned to service properly, and the sequence differs by release family.

Resetting a tension drop-off door (technician procedure)

Doors that release spring tension take the longest to put back, and it is not a job for guesswork. The sequence below is what a trained technician follows, and it is here so you understand why a reset can take time and why it is not something to attempt in house. Manufacturers differ and their written instructions always take precedence.

On motorized doors you may need to run the motor to the fully closed position first, to resynchronise the limit switches, then reopen and clamp. Electrical activation components are reset as the manufacturer describes.

Resetting a non-spring release door (technician procedure)

Because spring tension is never released, this is much easier and safer. Electrical systems often just need the alarm cleared and power restored, then the door run open with the operator. On manual systems you restore the links or reset the chain or cable to its armed state and open the door. Some motor-controlled units will not open after an alarm until the operator is reset with a key.

A door left in a released state after a test is a door that will not close in a fire. Whoever performs the test owns the reset.

8. Operating a fire door day to day

A fire door still has to work as a door, which is where the day-to-day compromises creep in.

• Direct drive is rarely used on fire doors. The operator has to disengage so the door can close on its own, which is why chain hoist and similar arrangements are common.
• Chain hoists on fire doors must allow the hoist to disengage, or automatic closing can’t happen at all.
• Hold-open is not a feature, it’s a violation unless it’s an approved release device that lets go on alarm.
• Emergency egress doors, typically rolling grilles, are a different design: over-sprung so they open on their own when the operator is released, with the operator’s internal resistance acting as a brake.
• Blocked openings are the common failure. Pallets stacked in the opening, a chain padlocked through the curtain, or a disabled release are all the same problem with different appearances.

9. Installing and specifying a fire door correctly

A fire door that is specified wrongly or fastened to the wrong wall cannot be rescued by good hardware. Most of the errors that surface at inspection were made before the door arrived. This section is here so you can judge whether the company installing your doors is doing it properly, and so your own specification and site conditions hold up their end.

Read the specification first

The bid specification usually carries the installation, safety and documentation requirements, not just the door description. It normally states the rating and class, who prepares the opening, the acceptable manufacturers (and any “or equal” clause), the curtain, guides, counterbalance, brackets and hood, the operation type, and the closing devices. Closing devices are often the most difficult part to interpret, because architects rarely state more than “must close”.

The specification will also commonly demand a drop test, sometimes witnessed by a representative of the end user, and may require an installer with a stated number of years of experience. Use a drop test form signed off by the customer or AHJ and by the technician.

What the opening has to be made of

The rating of a fire door depends on what the guides are fastened to. The listed jamb details specify minimum fasteners of 3/8 inch diameter, edge distances measured as multiples of the bolt diameter (6 times from either edge, 8 times into the masonry), and a minimum 2500 psi concrete or brick.

Steel members have to be allowed to expand in a fire. The listed details call for an expansion gap of 1/8 inch for each foot of opening height where a guide angle is welded to a steel jamb, and metal shims between the guide wall angle and the wall where the steel stops at the header. Unfilled block can be used only with a threaded rod and crush plate arrangement, not with a simple surface fastener.

What a competent installer does on site

• Paperwork and parts. Check the paperwork, verify every crate and component against the manufacturer’s parts list, and review the instructions and drawings for the door and any accessories.
• Site rules. Many sites need specific PPE, safety training or hot work permits. Notify other trades and secure the opening area.
• Assess the opening. Jambs must be plumb, level and square. When removing an old door, clear old welds and debris and finish repairs first. It is the installer’s job to verify the wall suits the fire rating and can carry the door’s weight, and to tell management about any discrepancy, because staying silent increases exposure to door failure and liability.
• Space. Verify the opening, clearances and side room against the approved shop drawing. Fire doors usually need extra headroom for release cable runs, electrical release devices, fuse links, pulleys, eye bolts and the dropout mechanism.
• Future trades. HVAC, communications or cranes added later must not impede the door closing. Nothing can be attached to the door and nothing stored where it could block it.
• Hardware. For fire rated products the hardware must come from the manufacturer. If it cannot be used, any substitute must be approved by the manufacturer.

Guides, expansion and fasteners

Proper guide installation gives smooth operation, reliable drop-outs and agency compliance. Guide spacing must follow the installation manual and the guides must be plumb. If either is wrong, the fire and wind load ratings may be void, and the manufacturer should be contacted any time field conditions differ from the approved drawings.

• Measure the floor slope and shim as required.
• With downward guide expansion, shim both guides off the floor.
• With upward expansion, leave adequate space above the guide mounting angle.
• Fasteners must sit in the specified locations within the mounting slots, using the supplied washers and fasteners.

Hanging the curtain and setting tension

Smaller doors can have the curtain rolled onto the barrel on the floor. Larger doors are slung to reduce the lifting weight, with the tension end of the barrel, which holds the springs, treated as the heavier side when placing straps. Whichever method is used, the barrel has to be level, the coil restrained from unrolling, and the bottom bar fed into the guides and clamped before the stops go on.

Finish with the hood, including intermediate supports where required, and test the flame baffle if the door has one. Then fit guide and lintel seals, the tension and drive covers, and the safety and warning labels, clean up, and perform the witnessed second drop test and the form.

Relocating an existing fire door

Moving a rated door to a new opening is possible but not casual (DASMA TDS 285). The original label or certificate must be found, the door size cannot be field modified, the wall construction must match with the listed guide fasteners, and the rating has to be right for the new opening. Fusible link changes need original-manufacturer parts, and release devices must be compatible with the new alarm system. Check leakage rating requirements where they apply, the door’s age and condition, and whether installation instructions and drawings still exist. The AHJ has the final say on approval, including what happens to the old opening if it is abandoned, replaced or left open.

Rating classes, label requirements and the wider compliance picture are covered on our fire door ratings page and fire door overview. For the general anatomy of a coiling door that isn’t fire rated, see the rolling steel door guide.

Frequently asked questions