Bulletin 30-40 / June 1999

Rigid Round Duct (UPC-87)

Specifications and Installation
Instructions

PACKING LIST General Properties

Part No. UPC-87-XR Inside Diameter 7 inch (178 mm)
Thickness 1 inch (25 mm)
Each carton contains X lengths of:
Length 6 feet (1.8 m)
6 ft. (1.8 m) duct with ship lap joints
Air Velocity (max.) 4000 fpm* (20.3 m/s)
APPLICATION Service Temperature (max.) 250°F (121°C)
Positive Pressure (max.) 8 in. w.c.* (1992 Pa)
Rigid Round fiberglass duct, manufactured by Johns-
Negative Pressure (max.) 2 in. w.c.* (498 Pa)
Mansville, is designed for use as a plenum for all Unico
*Rigid Round Duct has been UL tested at 2½ times the recommended
Systems.
velocities and at 2½ times the recommended internal pressures.

For all 1218 and 2436 systems, the duct can be mounted Thermal Conductivity (ASTM C 518)
directly to the blower module using the UPC-93 Plenum
Adapter and the UPC-61 round plenum adapter. Mean Temperature, °F (°C)
50 (10) 75 (24) 100 (38)
For all 4260 systems, first connect at least a 4-foot (1.2-m) k .22* (.032**) .23* (.033**) .24* (.035**)
section of 9-inch (229-mm) round metal duct to the plenum * Btu•in/(hr•ft²•°F)
adapter. Then either split the flow 50/50 using a 9 x 7 x 7- ** W/m•°C
inch (229 x 178 x 178-mm) metal tee before using the rigid
round plenum, or continue to use the 9-inch (229-mm) Underwriters Laboratories
metal duct until 40% of the air is removed. Then use the 7- Surface Burning Characteristics
inch (178-mm)rigid round. (UL 723)
Listed by UL as Class 1 complying with (UL181)
Note — When using metal duct, tape every seam “Standard for Safety for Air Ducts”.
with aluminum tape and insulate with at least 1- Flame Spread not over 25
inch (2- mm) of fiberglass insulation blanket or Smoke Developed not over 50
sleeve. Also, use a foam saddle under any support
straps to prevent condensation.
molded sections are covered with tough, abuse-resistant,
UL-approved scrim reinforced foil jacketing.
DESCRIPTION
An exclusive feature of Rigid Round Duct is an integral
Johns-Mansville Rigid Round Duct is a high pressure, high high density “slip-joint” which makes possible strong, snug
velocity, preformed fiber glass duct specifically designed connections between sections. No expensive tools or
for VAV energy efficient heating and cooling systems. equipment are required for installation.
Made from strong, flame-attenuated glass fibers, it is
designed to provide thermal insulation, vapor retarder, and
acoustical absorption in one product. The cylindrically

Note — Specifications, Ratings, and Dimensions are subject to change without notice.
© Copyright 1995-1999 Unico, Inc.
Bulletin 30-40 — Page 2

INSTALLATION Note: A general rule for shelf life is 2 years.

Exposure to high heat may accelerate aging.
Tools required:
Consult the tape manufacturer for more detailed
– Knife
shelf life information.
– Slip-joint cutter (or utility knife)
– 3 inch wide Aluminum tape as follows: Surface Preparation. In order to obtain satisfactory
UL 181A-H heat activated tape (UPC-17) adhesion and bonding, the surface on which the closure
or UL 181A-P pressure sensitive tape will be applied must be clean and dry. Dust, dirt, oil,
grease, moisture and similar substances may result in
Optional tools:
adhesion and bonding failure when present. Often, wiping
– Heat iron for UL 181A-H tape capable of
the application surface with a clean, oil-free, lint-free rag
maintaining a surface temperature of 550°F to 650°F
or paper towel is sufficient. However, for the best results
(288°C to 343°C).
on contaminated or questionable surfaces, the cleaning
– Tape squeegee for UL 181A-P tape
recommendations of the tape manufacturer should be
– GSH Metal reinforcement washers
consulted.
– #10 x 1.5 Sheet metal screws
Application above 50°F (10°C). Using 2½-inches (64-
Insert the male end of the slip-joint into the female end of
mm) wide (minimum) tape, position the tape along the
another section of duct. Use a slip-joint cutter or utility
edge of the joint in a manner that will allow 1-inch (25-
knife to form ends if necessary. Ends properly cut will fit
mm) minimum overlap on adjacent surfaces, (see North
snugly.
American Insulation Manufacturers Association (NAIMA)
Seal the joints with an approved closure method described publication #AH119, Fibrous Glass Residential Duct
below. Overlap the joint 1-inch (76 mm) min on either side Construction Standards). While holding the tape taut, press
of the joint, (see North American Insulation Manufacturers in place taking care to avoid wrinkles and folds. Rub tape
Association (NAIMA) publication #AH119, Fibrous Glass firmly with a plastic squeegee until the facing
Residential Duct Construction Standards). reinforcement (scrim pattern) shows through the tape.
When joining to a metal duct, use one of the standard Application below 50°F (10°C). If tape has been stored
taping methods below. If additional strength is required, at temperatures less than 50°F, it should be conditioned
use sheet metal screws through sheet metal washers. prior to use by placement in a warm environment in order
to improve the initial tack.
UL 181A-H Heat Seal Closure. Heat and pressure
should be applied until the green ABI dots have darkened. Using any suitable heating iron with the plate temperature
After heating the closure, use the surface of the iron, a set at 400°F ± 25°F (204 ±14°C), preheat the area to be
leather glove, or other heat-resistant tool to press the taped. Quickly position the tape on the preheated area and
closure into the duct facing scrim pattern. Use a press in place. Pass the iron two or three times over the
combination of heat and pressure to rub the closure into the taped surface using a rapid “ironing” motion.
facing for best results.
Complete the bond by rubbing the tape firmly with the
Note: Open flame alone must not be used on heat plastic squeegee until the facing reinforcement shows
seal closures. Heat alone is not sufficient to through the tape.
provide a good bond; physical pressure (typically
applied by smearing action) is also necessary. SUPPORT
UL 181A-P Pressure Sensitive Tape Closure. The Rigid Round duct should be hung so that the hanger will
following information applies only to pressure sensitive not damage the duct facing. Straps or saddles in contact
tapes. For specific storage and installation instructions, with the duct should be fabricated of 24 gauge galvanized
refer to the data sheets provided by the tape manufacturer. sheet metal, with a minimum width of 1-inch (25-mm).
Sheared edges, or any burrs, should be rolled to the outside
Shelf Life. Pressure sensitive tapes often have storage
of the hanger. Hangers should not exceed 6-feet (1.8-m) on
requirements and shelf life limitations. The installer should
center, and should be located as close to the duct joints as
verify that these conditions have not been exceeded prior
practical.
to use.
Bulletin 30-40 — Page 3

3. Bend the starting Bend

flange to
edge of the spin-in start
thread
(UPC-23B) takeoff
thread flange as
shown in Fig. 2.
Then twist the
1" (min.)
spin-in into the Stub Thread Flange
24 gauge
hole. Be sure that
Tape Ring Gasket
the bottom flange IL00092.CVS

is fully engaged on
the inside of the Figure 2. Spin-In Takeoff
1" (min.)
plenum. It may be (for 1" Fiberglass Duct)
24 gauge necessary to apply
some pressure as you spin the takeoff a full 360°
around. Inspect the inside of the takeoff to be sure
no insulation from the plenum is projecting into the
airstream. Continue to spin the takeoff until no
excess insulation can be seen down inside the stub
of the takeoff.
il00199.CNV

1" (min.) CONNECTING DUCT TO TAKEOFF OR TERMINATOR

24 gauge

1. Pull back the insulation of the supply tubing about 2

inches (5 cm) to expose the inner core.
2. Slip the core over the stub of the takeoff or
terminator as far as you can. Then secure with clamp
PATCHING using clamp pliers (UPC-54).
3. Stretch the insulation and outer jacket over the core
Accidental punctures or tears in the facing should be
and stub and stuff under the tape ring as best you
repaired to minimize leakage and provide a neat
can. Secure the outer jacket with UL-181A
appearance.
aluminum tape.
If the damaged area is small, repair with approved closure
system above. Where larger areas of the facing have been
damaged, remove the section of damaged duct. Replace
with a new duct, using lap joints at both ends.

PLENUM TAKEOFF INSTALLATION

Plenum Takeoff Installation. Position the plenum
takeoff so that the least amount of stress is applied to the
connection and the duct is as straight as possible. Usually,
the takeoff should be positioned in the 4 or 8 O'clock
position (Fig. 1).

15
IL00096

Figure 1. Plenum Takeoff Location

For 1-inch (2.5-cm) fiberglass plenum:
1. Use a UPC-55 hole cutter ("cookie" cutter) to make
a 2-inch hole in the plenum.
2. Cut a ½-inch slit in the plenum jacket.