Some frequently asked questions and tips on our most popular products.
Sealants, Adhesives, Gaskets
PROseal and FIBERseal are premium-grade duct sealants capable of sealing ductwork up to 15″ w.g.
FIBERseal contains fiber, PROseal does not.
EVERseal and EZ-seal are economy-grade duct sealants, capable of sealing ductwork up to 10″ w.g.
EZ-seal contains fiber, EVERseal does not.
Because TDC/TDF connections are single thickness, they tend to deflect more than Ductmate connections when compressing the gasket to make the connection. Sticky Tape is made from a softer compound to allow for this difference.
Ductmate’s 440 Butyl Gasket is firmer material specifically engineered to be used with our Ductmate Flange Connection System. It can also be used with other slide on connection systems.
PROseal, FIBERseal, EZ-seal, EVERseal and SOLVseal can all be used outdoors. They must be kept dry until completely cured. If rain or snow is suspected after applying any of the sealants, you will need to cover the duct until the sealant has fully cured.
Yes, PROseal, FIBERseal, EZ-seal, EVERseal and SOLVseal can be painted using a water-based or epoxy-based paint. The sealant must be fully cured before painting. Spot test first to make sure results are acceptable. (Sometimes paint will crack or “fish eye”, which only effects the appearance and not the performance of the sealant).
The joint can be sealed from the inside or the outside of the duct. If the ductwork is exposed, it may be more aesthetically pleasing to seal from the inside.
Ductmate water based sealants, adhesives and coatings meet the LEED requirements for Low-Emitting Materials for Indoor Environmental Quality, Credit 4.1, often abbreviated to LEED EQ 4.1.
The following are general guidelines; please consult your local regulations regarding disposal. The best way to dispose of these products is to use it all on the duct. The less product in the bucket, the easier it is to dispose. If the product has cured (dried) in the bucket it can be disposed of with regular trash. This applies to water and solvent based products. If dealing with large amounts of material, you can pour it over shredded paper or cardboard to accelerate the curing time and once cured it can generally be disposed of with regular trash. Since local laws and regulations can vary greatly, we recommend that you consult your local code office or trash hauler to determine what is allowable.
PROseal Spray can be applied using most commercial-grade paint sprayers. Graco’s 390 Airless Electric Sprayer is an entry level model perfectly suited for PROseal Spray. Whichever spray system you choose, make sure the pump is capable of supporting a minimum .021” tip size. Always follow spray equipment manufacturer’s instructions when using spray equipment.
For best results, use a Spray Tip with 2”- 4” fan pattern and minimum .021”-diameter orifice. Fan patterns are indicated by doubling the first digit of the Spray Tip model number. For instance, a 121 tip provides a 2” pattern and a 221 tip provides a 4” pattern. The last two digits of the model number indicate orifice diameter in thousands of an inch, i.e., .021”.
- Sandwich Access Doors (Insulated, Un-insulated, Clean-out, Circular, and Observation): 20” positive w.g. and 10” negative w.g.
- High Temp Sandwich Doors: F1 & F2: 14” positive w.g. and 10” negative w.g.
- Framed Access Doors (low pressure): 3” positive w.g. and 3” negative w.g.
- Framed Access Doors (high pressure): 10” positive w.g. and 3”negative w.g.
Sandwich (insulated/uninsulated) Doors and Square Framed Doors:
Yes, the doors can be used outdoors under normal weather conditions. As long as the doors are not susceptible to sitting submerged in water there should not be a problem. However, an eave or deflector plate should be installed above the door as a preventable measure, as continuous or sheeting rain could permeate the gasket. Both the door and the ductwork will be exposed to the same weather conditions, so if the duct rusts, so will the door.
Sandwich (F1/F2) and Ultimate doors:
All common gaskets that will resist temperatures at or above 1500 degrees Fahrenheit are hygroscopic. This is a fancy way of saying that they like to absorb liquids. With that in mind, access doors that are used on rooftop applications will need to be protected from the weather in some fashion. Typically, access doors that are installed on the side of the duct (recommended) can be shielded with a simple deflector plate over the top of the door. This will keep rain and or sheeting water from impacting the top gasket directly. Another method is to seal the top and sides with silicone caulking. The caulking can be applied directly to the gasket material. For entry into the door, the cleaner would need to cut the caulking with a razor knife and then reapply once the duct has been serviced and the door replaced. If the door must be installed on the top of the duct, the silicone caulking would need to be applied to all four sides of the door. In either case, the caulking will not compromise the fire resistance of the door.
Insulated round and rectangular Sandwich Access Doors have a rated R-value of 2.1. Our Square Framed Access Doors have a rated R-value of 4.2.
Ductmate does not manufacture fire rated access doors. Fired rated doors are utilized when providing access in fire rated walls and ceilings.
No. We recommend the F2 access door as its ceramic fiber gasket allows its use with temperatures up to 2300°F, therefore meeting the requirements set forth in NFPA96 standards which require a gasket with a minimum service temperature of 1500 degrees Fahrenheit.
Yes, our Sandwich Access Doors are available for round or spiral pipe. For grease duct applications, we now offer our UL1978 Listed Ultimate Round Access Door.
Measure opening if possible or use this formula: Diameter = circumference divided by ( π ) 3.1416
The circumference can be measured with a flexible tape measure.
Outdoor installations shall be UV—resistant Hypalon coated woven fiberglass fabric.
Hurricane Air Brace
Air conditioning stands do not require a Notice of Acceptance (NOA) per the Florida Building Code. Our product would not need to have an approval from Miami Dade as it is based on calculations, and all that needs to be done is for the contractor to submit the design to the Building Official with the raised seal drawing from the Engineer.
Slip & Drive
Yes. Our Hemmed S Slip is available straight end only 6” through 24” in 2” increments.
- Drive Slip 4” through 26” in 2” increments
- Drive slip with straight end with 45° bevel or Tabbed end with 45° bevel
(all the above can be manufactured in 1” increments upon request)
When spacing the Clutcher System, please stay within the working load limits of the Clutcher size being used (ex: if using CL20, they would be spaced so that the vertically hung Clutcher is supporting no more than 250 lbs.) Be sure to calculate total weight including connectors, registers, etc. There is usually a maximum of 10’ spacing. Consult the Clutcher spec sheet for working loads of non-vertical supports. Spacing requirements should meet and not exceed SMACNA weight load limits.
No. The Clutcher system’s wire rope is an aircraft quality wire rope that has been tested with the Clutcher as a system. The chambers on the Clutcher that you feed the aircraft cable through are perfectly sized to fit our Ductmate cable. This precision fit is what allows the product to consistently perform at the designated weight load limits.
If other wire rope is used with the Clutcher, Ductmate will no longer assume any responsibility or guarantee the system.
Ductmate’s Clutcher system has been tested and approved by SMACNA per Chapter 4, Hangers & Supports, HVAC Duct Construction Standards, Metal & Flexible, 2nd Edition for use in hanging both spiral and rectangular ductwork. We will furnish copies of the approval letters on request.
No, the Clutcher should not be used where chlorine or any corrosive or extremely humid conditions are present.
Round Connector Systems
The pocket will accept up to a 12 gauge Longitudinal seam.
Small profile is available from 8’’ to 30’’. The large profile starts at 30’’ and can be made up to 72’’.
The difference in the two profiles is the gauge of steel. The small profile has 22 gauge flanges with a 20 gauge closure band. The large profile has 20 gauge flanges with an 18 gauge closure band.
- Small Profile – not used with gauges heavier than 20 gauge or lighter than 28 gauge
- Large Profile – not used with gauges heavier than 16 gauge or lighter than 28 gauge.
Ductmate’s Quick Sleeve round duct connector can be used to access the inside of round pipe for cleaning, viewing, etc., when a standard access door will not work. Following are instructions when installing Quick Sleeves to access the inside of pipe.
- Use two Quick Sleeves.
- Cut about a one foot piece out of the pipe that you will need to access.
- Slide a Quick Sleeve on each open end of the installed pipe (not the piece you cut out).
- To complete the assembly, put the one-foot piece of pipe back in the opening it was cut out of and slide each Quick Sleeve over the cut openings of the pipe and tighten the bolt on the Quick Sleeve. This will give you an air-tight seal.
- When you want to access the pipe, loosen the bolt on each Quick Sleeve and slide the Quick Sleeves back over the pipe, away from the one-foot piece, remove the one-foot piece of pipe and this will give you plenty of access for cleaning, viewing, etc.
- To re-install the one-foot piece of pipe, follow the instructions in #4 above.
Ductmate can be used on rooftop applications. Instead of 6” cleat, use 10’ continuous metal cleat on top duct flange to prevent water from collecting on the gasket. Do not use PVC (plastic) Cleat outdoors.
Yes, DM35 is an accepted breakaway connection. Please refer to the last page of the Ductmate “25/35/45” installation instructions for further information.
The common size is a ¾” or 1” screw.
Ductmate Frame List formula gives you the total lineal footage needed in a given duct line.
Formula: (Width of Duct in Inches + Height of duct in inches)/ 3 = total lineal feet of flange needed per joint
If you multiply this number by the number of joints of the same size needed, it will give you the total lineal feet for that given duct line. Keep in mind that the number of joints needed is one more than the number of duct sections that you are fabricating.
Duct size: 40” x 30”
Feet per joint: 40 + 30 = 70 / 3 = 23.33 lineal feet (lf.) per connection
Number of Sections: 5 sections of duct
Number of Joints: 6
Total Flange Needed: 23.33 lf/joint x 6 joints = 139.98 lf.
You would order 140 lf. of Ductmate flange.
Both 304 and 316 stainless are from the same stainless steel family. They are the most common types of stainless specified and used in the fabrication of ductwork because they can be worked with standard sheet metal equipment. In general, 316 will offer better chemical resistance than 304 but is more expensive. As with any specialty application, the contractor and engineer of record should agree on the proper material for the project prior to fabrication of the duct is started.
No. Ductmate products are considered to be mechanical. Mechanical, electrical and plumbing components are not included in the calculations of these LEED credits.
Corners: approximately (1) corner for every (3) lf. of flange
Cleat: approximately (1) 6” piece of cleat for every (4) lf. of flange
Gasket: approximately (1) lf. of gasket per every (2) lf. of flange
Nuts & Bolts: If using a bolted corner, you will need half the amount of nuts & bolts as corners ordered.
Example: a box of 250 corners would require 125 nuts & bolts.
If using the no-bolt corner, the corner clips are in the box with the corners. You don’t need to order the corner clips separately.
Vane and Rail
While SMACNA does address the maximum unsupported height of a vane, there are no rules spelled out in SMACNA as to when to switch from a 2” to a 4” vane when it comes to duct width. A good rule of thumb would be that if there would be less than 4 turning vanes across the diagonal of the mitered elbow, then go to the smaller vane. Further to that, if the elbow is so small that less than 4 two inch vanes would fit across the diagonal, the contractor should consider making a radius elbow for that application. If there are less than 4 vanes in the elbow, the inner and outer voids at the heel and throat could cause enough turbulence to affect the overall performance of the elbow. At four vanes and up, this effect is minimal versus the rest of the elbow cross section.
- Determine the length of rail needed (distance across throat of elbow in inches) and divide the length by the distance between PROrail tabs – 2-1/8″ if using 2″ PROrail or 3-1/4″ if using 4″ PROrail. This will give you the number of pieces of turning vane needed.
- Determine the height of the turning vane in the elbow in inches. Multiply the number of pieces needed (as obtained in step 1) by the height of the vanes. This will give you the total inches of vane needed.
- Divide the total number of inches needed (as obtained in step 2) by 120 (10’ vane is 120” in length). This will tell you how many 10’ total pieces of vane to order.
Length of rail = 36”. Divide 36” by 2.125” (2-1/8”). Answer = 16.94” or 17 pieces.
Height of vane = 18”. Multiply 17” x 18”. Answer = 306”.
Divide 306” by 120” = 2.55 lengths of vane. Round up final answer (unless it is a whole number). 2.55 is rounded up to 3 pieces of 10’ turning vane, or 30’.