All About Spirals

Shoemaker Mfg. produces the most comprehensive spiral grille offering in the HVAC industry. Shoemaker spirals are a perfect fit aesthetically and functionally for the ever-popular exposed ceiling designs. All Shoemaker spiral models have adjustable blades, are made from galvanized steel, come standard with nylon bushings to prevent metal on metal rattling, have foam gaskets for an airtight seal, and are available in single or double deflection models. Dampers are not standard, however, all spiral models can be paired with a screw-driver operated opposed blade damper, or can be fitted with a full or half scoop if desired. Finish options include ten high quality powder coat designer colors or custom colors to match ducting.

Spiral Subgroups

Radial Spirals

Radial Spirals

  • Radius Spiral Pipe Grilles have a one piece curved frame with gasket to fit flush to the spiral pipe.
  • The blades are adjustable and allow up to a 4 way air flow.
  • Manufactured to fit a specific size of spiral pipe. See tables below and the “How to Measure” brochure for more sizing information.
  • Series include: RS34 and RS52
Transition Box Spirals

Transition Box Spirals

  • Choose between several face types: linear bar, perforated, lattice or standard blade.
  • The SD Series Grilles have a curved saddle with a gasket to provide an airtight fit to the spiral pipe.
  • The transition box allows for the damper to be out of the air stream.
  • Manufactured to fit a specific size of spiral pipe. See tables below and the “How to Measure” brochure for more sizing information.
  • Series include: SD34 and SD52
Universal Spirals

Universal Spirals

  • Universal Spiral Grilles are designed to fit a range of pipe sizes, from 4” – 48”. See tables below for more sizing information.
  • Designed for wholesale stocking distributors for greatest flexibility when duct sizing is not known.
  • Two kinds of high quality foam gasketing for a tight seal with the duct.
  • Series include: USR34 and USR52

Relevant Literature and Case Studies


Q: I have a competitor’s spiral that I am trying to match. How can I find out what the Shoemaker Mfg. equivalent is?

A: Use our handy Cross Reference.

Q: Why should I use one particular spiral series over the other?

A: There are many great reasons to use Shoemaker spirals. Select the one that best fits your needs.
  1. Shoemaker Mfg. manufactures three distinct lines of spirals: the Radial Spiral Pipe Grille, Transition Box Spiral Pipe Grille and the Universal Spiral Grille.
  2. The Radial Spiral Pipe Grille is flush to the pipe for a clean modern look.
  3. The Transition Box Spiral Pipe Grille is a style that has been around for years and allows the damper to be out of the airstream.
  4. The Universal Spiral Grille is more versatile in that one size can fit a range of pipe sizes.
  5. All three styles are standard without a damper but are available with an optional opposed blade damper (OBD), full scoop (FS), or half scoop (SC).

Q: What kind of damper or air control options are available in the spiral series?

A: The spiral pipe grilles are standard without a damper but are available with an optional opposed blade damper, full scoop, or half scoop. The opposed blade damper (OBD) is recessed screwdriver operated and has blades that oppose each other as they close which provides great air control. The full scoop (FS) is screwdriver operated to lift and lower the scoop which extends the full length of the grille and scoops the air up to flow through the grille. The half scoop (SC) works similarly to the full scoop but does not block the air from flowing past the grille when it is fully open.

Q: Will the Universal Spiral Grille fit on any pipe size?

A: The Universal Spiral Grille is manufactured to fit on a range of sizes based on the grille size. The chart below shows the pipe size range available based on the grille size you are ordering.

Q: Does the spiral pipe grille come with a template so I know what size hole to cut in the duct?

A: The spiral pipe grilles do not have a template. The size of the hole you would cut in the duct would be the size of the grille ordered. For example: if you order a 10X4 spiral pipe grille, the hole size you would cut would be a 10X4.

Q: What type of gaskets are used on the spiral grilles?

A: All three types of spiral grilles have a soft foam gasket to help seal the grille to the duct and reduce air lose. The Universal Spiral Grille also has a dense foam gasket on the ends of the grille to provide a close seal allowing the flexibility to fit on various pipe sizes in the range of that grille size. Below are images of the gaskets.

Q: What type of blades are on the Sprial Grilles?

A: All three spiral grilles have individually adjustable blades that are made of galvanized steel with 2/3" blade spacing. They are available in single deflection (RS52, SD52, USR52) with blades parallel to the shortest dimension or double deflection (RS34, SD34, USR34) with front blades parallel to shortest dimension and back blades parallel to longest dimension.

Q: What if I need more capacity than the spirals listed here can produce?

A: Shoemaker Mfg also carries two different Drum Louver products that are great for long throw applications such as sports arena, gymnasiums, conference centers, industrial plants and other large spaces. See the Drum Louvers (DL) and the Spiral Duct Mount Drum Louver (DLS) product pages and the Spiral Duct Diffuser flyer above.

Q: Can I return spiral grilles if they don’t fit?

A: Because our Radial Spiral Pipe Grilles and Transitions Box Spiral Pipe Grilles are manufactured to the specifications required for each job, we cannot accept returns. For the Universal Spiral Grille, there may be limits to the returns and will need to be approved prior to returning. Please review the appropriate submittals and talk to your Inside Sales Representative to answer any questions you may have, especially about the sizing and measuring before ordering.