GUIDE SPECIFICATION FOR

lami-ventTMLAMINAR FLOW diffusers

SECTION23 37 13 or 23 33 00

DIFFUSERS/REGISTERS/GRILLES or AIR DISTRIBUTION

NOTE TO SPECIFIERS: READ & FOLLOW INSTRUCTIONS IN ALL RED CAPS AND DELETE DIRECTIVES AND OPTIONS NOT SELECTED. ($) indicates an added cost for OPTION/FEATURE.

2.1SUPPLY DIFFUSERS

  1. TYPE ___ LAMINAR FLOW DIFFUSERS

1.Diffuser shall be ASHRAE Group E, non-aspirating laminar flow type suitable for use in critical environments and installation in accordance with ASHRAE Standard 170 for Operating Rooms.

2.Manufacturer’s published static pressure performance data for 24” x 48“ nom. size with 8” inlet shall not exceed 0.10” w.g. at design point of 30 CFM/sq. ft.

3.Diffuser shall utilize a two chamber plenum design. Air shall be admitted to the top chamber through an inlet collar and inverse conical balancing mechanism. The balancing mechanism shall be adjustable by turning a screw from the room side of the diffuser. Diffuser’s internal balancing damper must be capable of providing a fine adjustment of approximately 20-30%.

DESIGNER NOTE: Diffuser’s internal volume damper should not be utilized for only means of balancing. Dampers at branch takeoff should also be included in design.

4.The diffuser plenum shall be constructed of 0.063" extruded aluminum with mitered, back-welded corners and 0.040" aluminum top plate. No cracks or gaps in the sides of diffuser plenum will be allowed.Single chamber designs or designs utilizing flat or perforated plates to equalize flow are not acceptable. Manufacturer shall provide hanging tabs for independent suspension. OPTION FOR SPECIFIER CONSIDERATION ($):Manufacturer shall insulate the laminar flow diffuser with 1-1/2" duct wrap FSK-backed insulation of 0.75lb/c. ft. density to prevent heat gain and condensation.

5.A solid, 0.040” aluminum plate with two rectangular cutouts located directly above a V-shaped diffusion basket shall separate the top and bottom chambers. The lower chamber shall have a V-shaped, perforated diffusion basket mounted within a rectangular, perforated diffusion basket to evenly distribute air over the entire face of the diffuser.

SPECIFIER TO CHOOSE FACEPLATE STYLE BY SELECTING ONE OF THE FOLLOWING FACEPLATE STYLES:

For standard framed style aluminum faceplate:

6.Perforated faceplate shall be .050" aluminum. Perforations to be 16% open area for 40 or less CFM per square ft. of module, 23% open area for 45-65 CFM per square ft. of module, or 33% open area for higher velocities. Manufacturer shall provide vinyl-coated stainless steel cable safety retainers on two opposite sides to prevent accidental dropping of faceplate. The diffuser perforated faceplate shall be installed in an extruded aluminum mounting frame with mitered back-welded corners. No diffusion component may be affixed to the back side of the faceplate frame. The back side of faceplate shall be easily accessible for ease of cleaning.

For optional ($) wrap-around style aluminum faceplate:

  1. Perforated faceplate shall be .050" aluminum and shall extend over and wrap around plate frame on all four sides to assure continuous perforated surface appearance between ceiling tee frames. Perforations to be 16% open area for 40 or less CFM per square ft. of module, 23% open area for 45-65 CFM per square ft. of module, or 33% open area for higher velocities. Manufacturer shall provide vinyl-coated stainless steel cable safety retainers on two opposite sides to prevent accidental dropping of faceplate. No diffusion component may be affixed to the back side of the faceplate frame. The back side of faceplate shall be easily accessible for ease of cleaning.

For optional ($$) wrap-around style stainless steel faceplate:

  1. Perforated faceplate shall be 20 ga. 304 stainless steel with No. 4 polished finish and shall extend over and wrap around plate frame on all four sides to assure continuous perforated surface appearance between ceiling tee frames. Perforations to be 16% open area for 40 or less CFM per square ft. of module, 23% open area for 45-65 CFM per square ft. of module, or 33% open area for higher velocities. Manufacturer shall provide vinyl-coated stainless steel cable safety retainers on two opposite sides to prevent accidental dropping of faceplate. No diffusion component may be affixed to the back side of the faceplate frame. The back side of faceplate shall be easily accessible for ease of cleaning.

7.All exposed surfaces including border trim shall have finish of SPECIFIER TO SELECT ONE OF FOLLOWING FINISHES AND DELETE OTHER CHOICE(white baked enamel of suitable quality to withstand typical cleaning solutions and normal scrubbing commonly used in hospital operating rooms. OR 204-R1 clear anodized aluminum. ($))

8.Diffusers located in rooms with gypsum board hard ceilings shall be furnished complete with mounting frames. Verify exact locations of diffusers with architectural reflected ceiling plans where shown.

  1. Laminar flow diffuser manufacturer shall furnish individual plaster frames or extruded aluminum tee and angle framing sections for suspension as required by diffuser configuration. The tee shall be 1-1/2" wide x 1-7/16" high and angles shall be ¾” wide x 1-7/16” high. Minimum wall thickness of the tees and angles shall be 1/8”. DESIGNER NOTE: Centerline to centerline dimension of each framing section shall be 0.125” per lineal foot added to the nominal size of the laminar diffusers.
  2. The suspension system shall be factory-welded in sub-assemblies. Where framing sub-assemblies butt together, the adjoining surfaces shall be gasketed and mechanically-fastened with self-tapping wafer head screws.
  3. All tees and angles shall be pre-punched on 6" centers for independent suspension from above spaced at 2’ max.
  4. Manufacturer shall furnish 1/8" thick closed-cell polyethylene gasket tape to be field installed on the frame assembly to provide seal between diffuser/tee grid.
  5. The ceiling framing system shall be finished to match laminar flow panel diffusers.

9.Acceptable model and manufacturer: Lami-Vent™ by Precision Air Products Co. Nosubstitutes..

DIFFUSER OPTIONS FOR SPECIFIER CONSIDERATION:

FOR REMOVABLE PLUG BUTTON ($), ADD THE FOLLOWING TO SELECTED FACEPLATE PARAGRAPH 6. ABOVE:Manufacturer shall provide removable plug button for room-side access to volume adjustment valve without removal of faceplate.

FOR DIFFUSER WITH SIDE (or end) oval inlet ($), replace paragraph 2.1, A. 3. with the following:

3.Diffuser shall utilize a two chamber plenum design. Air shall be admitted through an oval inlet collar located on side (or end) of the upper plenum. SPECIFIER/DESIGNER NOTE: Elongated oval inlet reduces inlet area. Contact manufacturer’s Applications Engineer for assistance with sizing oval-shaped inlets and flexible duct sizesfor project-specific air volumes.

To specify all stainless steel lami-VentTM, consult factory for specification.

PART 3 – EXECUTION

3.1.INSPECTION/EXAMINATION

  1. The installing contractor shall examine all openings, mechanical and electrical work, and adjoining and adjacent construction to receive diffusers and plaster frames prior to commencing this work.
  2. The installing contractor shall field verify that the rough hard ceiling opening dimensions are as indicated within manufacturer’s submittals. Hard ceiling conditions shall be plumb and level with square corners to receive frames or framing sections. Openings not acceptable for installation shall be corrected by the appropriate contractor until conditions are satisfactory to installing contractor.
  3. The General Contractor shall coordinate corrective/remedial work promptly.
  4. Proceeding with the installation indicates the installing contractor accepts the rough hard ceiling openings and conditions.

3.2.INSTALLATION

  1. Provide balancing dampers on duct take-off to diffusers.
  2. Install air terminals where shown in accordance with manufacturer's instructions and reviewed submittals.
  3. Hang air terminals independently of the ceiling construction.
  4. Connect air terminals to air plenum branch supply ducts as per project plan details.
  5. Verify location of all components as shown on the manufacturer’s approved submittals.
  6. Where any adjacent welded ceiling framing sub-assemblies butt together with half-tees, the adjoining surfaces shall be gasketed and mechanically-fastened with self-tapping wafer head screws.
  7. Gasket tape provided by manufacturer shall be field installed on the top side of all horizontal ceiling grid surfaces as shown in manufacturer’s submittal. Gasketing to be installed after framing surfaces have been wiped clean, free from any construction dust.
  8. Provide inserts, power-driven type anchors, hangers or other Architect / Engineer approved hanger anchoring and suspension system devices and methods.
  9. Install suspended ceiling hangers plumb and free from contact with insulation or other objects within ceiling plenum not part of supporting structural or ceiling suspension systems. Splay hangers only where required to avoid obstructions and offset resulting horizontal forces by bracing, counter splaying, or other Architect / Engineer approved methods.
  10. Where width of ducts, cable trays and other construction within ceiling plenums causes hanger spacing to interfere with the location of hangers required to support suspension system members, install supplemental suspension members and hangers in the form of trapeze or equivalent Architect / Engineer approved devices. Size supplemental suspension members and hangers to support ceiling loads within performance limits established by referenced standards.

Form 4-105, effective 2/2016 Page 1 of 4