Pemko 4301 Surface Mounted Aut...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$143.04
$122.58
Pemko 4301 automatic door bottom, clear anodized aluminum, surface mounted, 3/4 in. drop, fire rated, retracted position showing actuator pin

Pemko 4301 Surface Mounted Automatic Door Bottom with 3/4" Drop Fire Rated

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Model: 4301CPKL36
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In Stock (leaves warehouse same day if ordered before 3pm ET)

$143.04
$122.58
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Pemko 4301 Surface Mounted Automatic Door Bottom, 3/4" Drop, Fire Rated

The Pemko 4301 is a surface-mounted automatic door bottom for wood or hollow metal doors in commercial applications. A plunger contacts the door jamb as the door closes, driving a drop bar seal down against the floor or threshold. Maximum drop is 3/4"; recommended gap under door is 1/2". Fire rated up to 3 hours on steel doors and up to 1-1/2 hours on wood doors. Aluminum case construction. Available in Clear Anodized or Dark Bronze Anodized aluminum with choice of EPDM Sponge Neoprene (RL) or PemkoPrene (PKL) insert.

Key Features

  • Automatic Operation: Plunger-actuated drop bar seal engages on door close; no manual operation required.
  • Fire Rating: UL10B and UL10C Positive Pressure tested; rated up to 3 hours on steel frames, up to 1-1/2 hours on wood doors.
  • Drop Capacity: 3/4" maximum drop; 1/2" recommended gap under door. Suitable for carpet installations.
  • Construction: Aluminum case with slotted holes for field adjustment during installation.
  • Sealing: Blocks draft, dust, moisture, insects, fumes, light, and sound transmission.
  • Low Closing Force: Minimal door closing resistance.
  • Warranty: 5 years.

Certifications and Ratings

  • Air Infiltration Tested: ASTM E-283-04
  • Sound Tested: ASTM E90
  • BHMA Certified: ANSI/BHMA A156.22
  • Smoke Tested: UL 1784, NFPA 105-2013
  • Fire Rated: UL10B, UL10C Positive Pressure

Technical Specifications

  • Model: 4301
  • Mounting: Surface mounted (semi-mortised applications)
  • Application: Wood or Hollow Metal Doors
  • Insert Type: RL - EPDM Sponge Neoprene; PKL - PemkoPrene
  • Material: Aluminum
  • Product Length: 36"
  • Height: 1-25/32"
  • Maximum Drop: 3/4"
  • Recommended Gap Under Door: 1/2"
  • Commercial/Residential: Commercial
  • Warranty: 5 Year

Typical Applications

  • Commercial office buildings
  • Educational facilities
  • Healthcare institutions
  • Retail establishments
  • Industrial and warehouse facilities
  • Multi-tenant residential properties
  • Government and municipal buildings

Product Specs

Features:
Recommended Gap Under Door is 1/2", Maximum Drop is 3/4", For Semi Mortised Applications
Application:
Wood or Hollow Metal Doors
Insert Type:
RL - EPDM Sponge Neoprene, PKL - PemkoPrene
Warranty:
5 Year
Product Group:
Door Trim and Accessories
Product Subgroup:
Door Bottom Sweeps and Door Shoes
Product Type:
Automatic Door Bottom
Subcategory:
Door Bottoms & Door Shoes
ANSI/BHMA:
Air Infiltration Tested ASTM E-283-04, Sound Tested ASTM E90, BHMA Certified ANSI/BHMA A156.22, Smoke Tested UL 1784, NFPA 105-2013, Fire Rated UL10B, UL10C Positive Pressure
Commercial/Residential:
Commercial
Product Model:
4301
Product Length:
36"
Product Dimension:
W: 29/2", H: 1-25/32"
Product Category:
Door Trim and Accessories
Product Substrate:
Aluminum
Department:
Door Hardware

Pemko 4301CPKL36 – Frequently Asked Questions

1) Will a Pemko 4301 automatic door bottom work on a fire rated door?
The 4301 is fire rated up to 3 hours on steel doors and up to 1-1/2 hours on wood doors, tested to UL10B and UL10C Positive Pressure. It is also BHMA Certified to ANSI/BHMA A156.22 and smoke tested to UL 1784 / NFPA 105-2013, so it covers both the fire label and the smoke seal line on a spec. It mounts to wood or hollow metal doors.
2) How big a gap under the door will the Pemko 4301 seal?
Maximum drop is 3/4 inch, and the recommended gap under the door is 1/2 inch. Set the undercut at about 1/2 inch and the drop bar has travel left to take up floor variation and carpet pile. If your existing undercut is more than 3/4 inch, this one will not reach the floor and you need a deeper-drop bottom or a threshold to close the gap.
3) Does the Pemko 4301 door bottom get mortised into the door or screwed to the face?
It is a surface mounted unit for semi-mortised applications, so the aluminum case attaches to the face of the door at the bottom rail rather than being fully routed into the door edge. Slotted mounting holes let you set the height and level it during install. That makes it a practical retrofit on doors already hung, with no routing needed on a fully surface application.
4) Do I need to cut a Pemko 4301 down to fit a 30 or 32 inch door?
The 4301 is supplied at 36 inches long, which covers a standard 36 inch commercial leaf. For narrower doors the aluminum case is cut to the door width on site, trimming from the end opposite the plunger so the actuating plunger still contacts the jamb when the door closes. Case body measures W: 29/2", H: 1-25/32".
5) What is the difference between the PemkoPrene and sponge neoprene inserts on the 4301?
Two seal materials are offered: PKL PemkoPrene and RL EPDM sponge neoprene. The sponge neoprene is the softer, more compressible seal, which suits an uneven or slightly out of level floor where the bar needs to conform. PemkoPrene is the alternative extruded insert. Both drop with the same 3/4 inch maximum travel, so the choice is the sealing face, not the reach.
6) Which finishes does the Pemko 4301 come in, and can I get either insert in either finish?
Two anodized aluminum finishes, clear and dark bronze, and each is offered with either the PemkoPrene or the sponge neoprene insert, so all four combinations are orderable. Aluminum case throughout. Dark bronze is the usual pick when matching bronze anodized frames or dark storefront trim; clear matches mill finish aluminum and 628 hardware.
7) Should I use an automatic door bottom or just a door sweep over carpet?
A sweep drags on carpet and wears out; an automatic door bottom like the 4301 stays retracted while the door swings and only drops when the door closes, the plunger hitting the jamb and forcing the seal down onto the floor. That is the reason to choose the automatic type over a fixed sweep on a carpeted opening, and why it is specified where a fixed sweep would create drag. It also seals draft, dust, moisture, insects, fumes, light and sound.
8) Will an automatic door bottom make the door harder to close on a classroom or patient room door?
The 4301 drop bar is built for low closing force, so it adds little resistance for the closer to overcome as the plunger is depressed. That matters on openings where the closer is already set light for accessibility. It also carries UL 1784 smoke testing and NFPA 105-2013, which is what a hospital or school corridor smoke barrier door needs from the bottom seal.
9) Can the Pemko 4301 be installed on an aluminum storefront or a solid core wood door?
The 4301 is listed for wood or hollow metal doors. Its aluminum case surface mounts to the bottom rail of either. For an aluminum storefront leaf, this is not the stated application, so specify a door bottom rated for that door type instead.
10) Can I use the Pemko 4301 to cut down noise and drafts between offices?
Yes, and it is tested for both: air infiltration to ASTM E-283-04 and sound to ASTM E90. The drop bar closes the undercut, which is the largest single leak path on a typical office door, sealing draft, dust, light and sound transmission when the door is shut. Rated commercial use.
11) Do the seal inserts on a Pemko 4301 get replaced, or do you replace the whole unit?
The seal is a separate insert in the aluminum case, ordered as either RL EPDM sponge neoprene or PKL PemkoPrene, so when the seal face is worn the insert is the replacement item rather than the whole bar. Match the insert type already in the case when restocking a building so the maintenance stock stays common across openings.
How fast can I get the Pemko 4301CPKL36 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 Pemko 4301CPKL36 come with a warranty?
Absolutely. The Pemko 4301CPKL36 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 Pemko 4301CPKL36?
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 Pemko 4301CPKL36 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.

Product Reviews

  • 5
    Seal

    Posted by Shane on Oct 25th 2025

    can be a bit overwhelming if not installed correctly double check you layout and you wont be disappointed

!