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Engineering Workshop

Get comments from our engineers about the development of AJ’s products. Not for the faint of heart.

HVAC Access Door Gasket Performance: The Best Is About to Get Even Better!

The hvac access door gasket for AJ’s very first access door back in the year 2000 was fantastic for its time: independently tested by Architectural Testing Inc, it achieved virtually zero total air leakage at pressures as high as 10” w.g. for an outswing door under positive pressure.  No other manufacturer’s door came close.

Water leakage at the time wasn’t quite the issue it is today, but as performance expectations rose, our zero-leakage for 15 minutes at –3” w.g. was soon unacceptable.

In 2002 we introduced the foamed TPE gasket that you are familiar with, and when we combined that with our cakepan door panel design in 2005, water performance shot up to zero leakage at –7” w.g…again, best in the industry.

Today, after 18 months in development and 1 year in laboratory testing and field service, we announce the next stage in gasket design…our hollow-core EPDM gasket.

EPDM – a flexible sponge rubber – is widely used in the automotive and HVAC industries for door and light seals, and general weather stripping.  EPDM is valued for low-temperature flexibility, and excellent resistance to compression set, atmospheric degradation, alkalis, acids, and oxygenated solvents.

And our unique design allows continuous, 1-piece application to the frame.  No more corner joints.

That all sounds good, but does this new AJ gasket design seal any better?   You bet it does: ATI tested our non-thermal 24×60 cakepan door to the ASTM E331 protocol and reported zero leakage at pressures from –1” to –20” w.g.!

We are pleased to report that this new gasket will be phased into production in the very near future, beginning with our 1.7” door models.

Texas Approval for Partner & Responder Doors

The Texas Department of Insurance has granted approval for A.J. Manufacturing Inc’s aluminum and steel-framed Partner and Responder door models to be used in designated catastrophe areas along the Texas Gulf Coast.

When installed in accordance with our instructions, the 21A Partner Door has achieved a Label Rating of +50, -43 psf, while the 41A Responder Door is rated +/- 50 psf.

TDI’s product evaluations can be found on their website at http://www.tdi.texas.gov/wind/prod/dr/dr497.pdf (Partner Door), and http://www.tdi.texas.gov/wind/prod/dr/dr498.pdf (Responder Door).

Water Leakage Troubleshooting Guide

We are committed to the industry’s highest standards of ACCESS door and wall panel performance and we recognize our products are part of a larger system of components that must work together for optimum results.  Click here for a trouble shooting guide and checklist.

AJ Product Testing

Hey… what are you doing in there?

  • Exterior entry doors used in high velocity coastal building zones must withstand a force of 140 mph.
  • The entrance door on a typical small commercial building opens and closes an average of 150,000 times a year.
  • An HVAC wall panel must not deflect more than 1/240th of its width.


Door Slammer

How can we be sure that our products will conform to building code requirements…or meet

customer expectations…or hold up under the wear and tear of extended use?

Fortunately, we have a lot of tools in our engineering workshop that allow us to do just that.

The Slammer… rapid cycle machine:

  • If we bolt an aluminum parting stop to a steel jamb, will it stay in place when the door gets blown shut by wind 100,000 times?
  • How about if we use self adhesive tape instead of bolts?

We’ve tested for both of those things and much more.

The cycle machine slams so violently that we usually have to shut it down for repairs several times during the test.

Slammer Slow Cycle

The slow cycle machine:

  • How much will our commercial door hinge wear after 1,000,000 cycles?

Just slow the slammer down to a crawl and we can find out.

The Shower Stall:

Need a place to experiment with different installation techniques in order to develop a weather-tight inswing door?  Just mount the door in the shower stall and get to work.  The nozzles meter out the equivalent of an 8” per hour rainstorm, and we can pressurize the

Pressure Wall Sprayer

booth to simulate a 34 mph wind to meet AAMA (American Architectural Manufacturers Association) specifications.

The Pressure Wall:

The pressure wall is a miniature replica of The Big One at Architectural Testing, Inc, an independent test lab in Saint Paul.  We don’t know of any other access door manufacturer that has one of these, and we have two!

  • How will leakage performance change if we switch from a perimeter style panel to a cakepan panel?
  • Will the self-adhesive access door gasket still seal against water leakage if it’s torn in the corner?

With the pressure wall, we can answer those questions.  We can generate positive or negative pressures more than twice as high as any air handler uses, and we can subject the door to the equivalent of an 8” hourly rainfall.  In essence, we can see how our door will perform under hurricane conditions!

What else?

Impact Test

When we can’t test it ourselves, or when we

need independent verification of our test results, we go to Architectural Testing.  Their pressure wall measures 33’ x 13’, and they have a lot of other test equipment.  For example, ATI has a cannon that fires a 10-foot 2×4 at 150 feet per second to

meet the “windborne debris” test criteria for the Florida Building Commission.  Here’s a picture

of one bouncing off our cakepan door.

ATI Deflection Test

Rack tests, sag tests, deflection tests, leak tests, cycle tests…it really goes on and on, and we do most of it right here.

  • How many latches should we put on an access door?  How many hinges?

Our customers look to us for the answers, and we can tell them!

Injected Polyurethane Wall Panels

Are you aware of the strength and versatility of injected polyurethane foam wall panels from A.J. Manufacturing?

Independent tests confirm resistance to deflection of 24g foamed steel panels manufactured by A.J. Manufacturing as follows:

  • For a 1″ panel with 48″ span, deflection is less than L/240 up to 15″ w.g.
  • For a 2″ panel with 48″ span, deflection is less than L/240 up to 31″ w.g.

Foamed panels are a lightweight alternative to mechanically fastened steel sheets.  A 2″ x 48″ x 96″ wall panel of 24g steel weighs just 92 lbs and supports a distributed load of over 5,000 lbs without exceeding L/240  deflection requirements.

We build panels to your size requirements with a choice of exterior skins, and interior reinforcements to meet your needs.  We even produce panels with a full thermal break

For more information, contact shempel@ajdoor.com.

Commercial Window Certification

Did you know?…


Thanks to recent improvements in product design, A.J. Manufacturing now offers several window models that meet the performance requirements of AAMA/WDMA/CSA 101/I.S.2/A440-08 for Light Commercial applications.

Our Model 500 Single Hung (Type H) meets Class LC-PG30; Model 905 Fixed Lite (Type FW) Class LC-PG70; and Model 900 Horizontal Slider (Type HS) Class LC-PG-30.

Installation tips for AJ Manufacturing’s HVAC Access Doors

Follow these four steps for trouble-free door operation:

1. Be sure the cabinet is level when you install our doors!


2. Shipping clips: use ‘em and lose ‘em.


All AJ access doors are packed with shipping clips.  These plastic or metal spacers are misnamed.  They’re really intended to be aids in the door installation process by maintaining the proper spacing of the door panel within the frame until installation is complete.  Once all frame installation screws have been tightened, remove and discard the shipping clips.

3. Seal the frame.


It’s essential that you provide a 100% effective seal between the cabinet wall and the installation flange of our door frame.  You can use foam tape or sealant, but whichever you choose, keep these points in mind:

  • The seal must be continuous all around the frame.  Be certain that there are no pinhole gaps in sealant.  If you use foam tape, force in extra material at butt joints so that it can’t shrink back.  Avoid overlaps of foam tape to insure uniform contact.
  • Foam tape should be 1/8” to 3/16” thick.  Any thinner and it may not fill surface irregularities.  Any thicker and it may cause waves in the installation flange between the installation screws.
  • If sealant is used, apply both under the installation flange prior to door installation, and again around the edge of the installation flange after door installation.
  • Do not pressurize the unit until sealant has had a chance to fully cure.  High operating pressures can blow pinholes through uncured sealant.
  • AJ applies sealant to the cut ends of the frame prior to frame assembly, so it’s important that you prevent frame corners from bending during handling and installation, or this seal will be broken.


4. Adjust the latch.


Improper latch adjustment is the #1 cause of field complaints!

  • Be certain that the door is square within its frame.  Loosen, re-square, and retighten installation screws if necessary.
  • Latch cams/pawls cannot be properly adjusted with the shipping clips in place, so remove and discard shipping clips before final latch adjustments are made!
  • There is a metal stop leg on AJ access door frames that prevents over-compression of the door gasket.  Regardless of which latch you have chosen for the door, for proper adjustment, the cam (pawl) of the latch must draw the door panel down to “kiss” the stop leg.  The door panel may flex slightly between latches, but it should touch the stop leg at every latch!
  • The door panel does not kiss the frame at the hinge side, and that’s okay.  Just be sure that it does on the latch side.
Properly adjusted latch

Properly adjusted latch

Improperly adjusted latch

Improperly adjusted latch