Zero International 364AA Sill ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$149.44
Zero 364AA Heavy-Duty Full Mortise Automatic Door Bottom

Zero International 364AA Sill Protection Automatic Door Bottom with Solid Neoprene Insert - Mortised - Heavy Duty

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Model: 364AA 36

In Stock (leaves warehouse same day if ordered before 3pm ET)

$149.44
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Zero 364AA Sill Protection Automatic Door Bottom with Solid Neoprene Insert - Mortised - Heavy Duty - Clear Anodized Aluminum

The patented automatic door bottom technology from Zero ensures an efficient seal against the floor or saddle. As the door is closed, the adjustable plunger is compressed against the door frame, activating a concealed flat spring mechanism. Zero door bottoms are designed to block penetration by air, sound, smoke, and flames.

  • Sill Protection Automatic Door Bottom
  • Mount: Mortised
  • Heavy Duty
  • Insert: Solid Neoprene
  • Finish: Clear Anodized Aluminum
  • Maximum effective drop: 1"
  • Rated for up to "B" label (1-1/2 hrs.)
  • Smoke Seal Rated
  • Sound Rated
  • Matching #364 End Caps are sold separately
  • Supplied with solid neoprene extrusion, self-extinguishing, under MIL R6855 Type II Class 40 oil resistant
  • Rated for 5 million cycles
  • ZERO’s patented automatic door bottom technology ensures a tight seal against the floor or saddle. As the door is closed, an adjustable "plunger" is compressed against the door frame, activating a concealed flat spring mechanism. This mechanism drops the seal smoothly from the housing in a scissor-like motion as illustrated below. The door seal compresses tightly even on uneven surfaces and retracts automatically when the door is opened.
  • All ZERO automatic door bottoms function the same way. The concealed spring mechanism causes the insert seal to activate on the hinge side first. It prevents the seal from dragging along the floor or threshold while the door is being closed to avoid door hang-up or closing delay.
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Product Specs

Commercial/Residential:
Commercial
Product Group:
Door Trim and Accessories
Product Subgroup:
Door Bottom Sweeps and Door Shoes
Product Type:
Door Bottom
Product Finish:
Clear Anodized
Performance Rating:
Fire Rated-UL10c
Product Substrate:
Aluminum
Department:
Door Hardware

Zero International 364AA 36 – Frequently Asked Questions

1) Can the Zero 364AA automatic door bottom be used on a fire rated door?
The 364AA is rated for use on doors up to a B label, 1-1/2 hours, and carries a UL10c fire rating. The neoprene insert itself is self-extinguishing, which is what keeps the seal from becoming a fuel source in the opening. If your opening carries a 3 hour A label, this is not the door bottom for it.
2) Should I use a mortised automatic door bottom or a surface mounted one?
The 364AA is a full mortise unit, so the housing sits inside a channel machined into the bottom edge of the door and stays hidden when the door swings. That means the door has to be prepped, which is easy if the door is being cut at the shop or is already off its hinges, and a real job if it is hung and in service. A surface applied door bottom screws to the face of the door and needs no machining, so it is the faster retrofit on an existing opening. Go mortised when you want the seal concealed, when the door is new or already down, or when a face applied housing would foul the frame stop.
3) How big a gap under the door will the Zero 364AA close?
Maximum effective drop is 1 inch, measured from the housing down to where the neoprene meets the floor. That covers most undercuts and the usual out of level slab, and the seal compresses tightly even where the floor is uneven, since it drops on a scissor action rather than sitting rigid. If your undercut is more than an inch, an automatic door bottom is the wrong fix and the threshold or the door itself needs to come up.
4) Do the end caps come with the Zero 364 automatic door bottom?
No. Matching #364 end caps are a separate line item and need to be added to the order. On a mortise install the caps are what closes off the ends of the routed pocket, so budget one set per door.
5) Does the Zero 364AA meet a smoke seal requirement on a corridor or stair door?
Yes, it is smoke seal rated, and it blocks air, sound, smoke and flame at the bottom of the opening. The undercut is the single biggest leak path on a smoke barrier door, and gasketing the jambs and head without addressing it leaves the opening open. Pair the 364AA with perimeter gasketing to seal the full opening.
6) Will an automatic door bottom drag on carpet or a finished floor every time the door closes?
It shouldn't. The seal stays retracted inside the housing while the door is in motion and only drops in the last part of the swing, when the adjustable plunger contacts the frame and trips the concealed flat spring. The insert comes down on the hinge side first, so it is not sweeping across the floor as the door travels, and it lifts back up as soon as the door opens. That is the difference between this and a fixed sweep, which rubs the floor on every cycle.
7) Is this door bottom rated for a high traffic entry or a stairwell that cycles all day?
Rated for 5 million cycles, and built as the heavy duty version of the 364 with an aluminum housing. For a lobby vestibule, a corridor cross door, or a stair door in a busy building, that is the class of unit to spec rather than a light duty seal.
8) Will a Zero 364AA hold up in a mechanical room or garage where there is oil on the floor?
The insert is a solid neoprene extrusion supplied under MIL R6855 Type II Class 40, which is the oil resistant grade, so it will not swell or break down the way an untreated rubber or vinyl bulb does around hydraulic fluid and lubricants. It is also self-extinguishing. That combination is why this one gets specified on equipment room and parking level doors.
9) Will an automatic door bottom actually cut noise coming under an office or hotel room door?
The 364AA is sound rated and uses a solid neoprene insert rather than a hollow bulb, so it compresses into contact with the floor instead of just brushing it. Sound follows the same path as air, and a 3/4 inch undercut is the leak that undoes gasketing everywhere else on the door. For a conference room, a guest room, or a demising door between tenants, the automatic bottom is the piece that closes it.
10) Can I adjust when the seal drops, or how hard it presses on the floor?
Yes. The plunger at the end of the housing is adjustable, and it is what sets the point in the swing where the seal engages and how far it comes down against the floor. If the seal is dropping too early and catching, or closing without contacting the floor, that plunger is the adjustment, not the whole unit. Set it after the door is hung and the closer is adjusted, since a change in closing speed changes how it feels.
11) What finish is the Zero 364AA and will it match aluminum storefront doors?
Clear anodized aluminum, which is the standard mill finish match for aluminum storefront and hollow metal frames finished to match. Since it is a mortise unit, most of the housing is buried in the door edge anyway, and the visible part is the end caps and the strip along the bottom.
How fast can I get the Zero International 364AA 36 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Zero International 364AA 36 come with a warranty?
Absolutely. The Zero International 364AA 36 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Zero International 364AA 36?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Zero International 364AA 36 from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.
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