Guide Specifications:

Dual Duct VAV Terminal Unit
HVAC Guide Specifications
Size Range: 45 to [LMHD] 7100 [LMHDT] 4500 Nominal CFM
Krueger Model Numbers:

LMHD – Basic unit, no mixing
LMHDT – Premium Unit, High Mixing, Constant Volume Flow Sensing

Part 1 – General
1.01	System Description: 
Variable air volume control box for installation in a ceiling that permits access to the unit. Manufacturer shall supply unit(s) of the design, number, size and performance as shown on equipment drawings and schedules. Unit(s) are for use in conjunction with air distribution manifolds, distribution ductwork and ceiling mounted diffusers.

1.02	 Quality Assurance:  
A.	Insulation shall meet NFPA-90A requirements for flame spread and smoke generation and UL-181 requirements for anti-erosion, corrosion and fungus properties.
B.	Sound power levels shall be ARI certified in accordance with the requirements of ARI-880-98.

1.03	DELIVERY AND STORAGE:
Units shall be stored and handled per manufacturer’s recommendations.

Part 2 – Products

2.01 Equipment

A.	General:
Factory-assembled, externally powered, variable air volume control terminal. Unit shall be complete with a damper assembly, flow sensor, externally mounted volume controller, collars for duct connection and all required features. Control box shall be clearly marked with an identification label that lists such information as nominal cfm, maximum and minimum airflow limits, coil type and coil hand, where applicable

B.	Unit Cabinet:
1.	[LMHD]Constructed of 22-gage galvanized steel with round or rectangular inlet collar and rectangular discharge with slip and drive connection. 
[LMHDT]Constructed of 22-gage galvanized steel with round inlet collar and rectangular discharge with slip and drive connection.
All primary air inlet collars shall accommodate standard flex duct sizes.

2.	Insulated with ½ in. thick, 1.5-lb. equivalent density mat-faced insulation that meets the requirements of UL181 and NFPA-90A.

3.	1” THICK INSULATION: (ALTERNATIVE TO ITEM 2) Unit casing shall be lined with dual density, 1” thick, 1.5 lb. density fiberglass insulation that meets UL181 and NFPA-90A.

4.	FOIL ENCAPSULATED INSULATION: ALTERNATIVE TO ITEM 2) Unit casing shall be lined with nylon reinforced foil-wrapped exposed edges, either 1’ or ½ ” thick, 1.5 lb. density fiberglass insulation that meets UL181and NFPA-90A.

5.	STERILINER INSULATION:(ALTERNATIVE TO ITEM 2) Unit casing shall be lined with 13/ 16 ” thick, 4 lb. density, rigid board insulation with nylon reinforced foil covering insulation fibers that meets UL181 and NFPA-90A. Liner shall be attached to unit casing by insulation adhesive and full-seam-length Z-strips to enclose and seal the insulation cut edges.

6.	NO LINER: (ALTERNATIVE TO ITEM 2) Unit casing shall be equipped with no internal insulation liner.

7.	STERILWALL INSULATION: (ALTERNATIVE TO ITEM 2) Unit casing shall be lined with either ½ ” thick or 1” thick, 1 ½ lb. density insulation, meeting UL181 and NFPA-90A, enclosed between the unit casing and either a non perforated internal sheetmetal cover extending over the fiberglass insulation, as well as covering the liner cut edges. Alternate: and a 23% perforated internal sheetmetal cover extending over the fiberglass insulation, as well as covering the liner cut edges.

8.	CELLULAR INSULATION (ALTERNATIVE TO ITEM 2) Unit casing shall be lined with 3/8” thick, smooth surface, closed-cell elastomeric thermal insulation for fiber free application and affixed with mechanical fasteners. 

C.	Damper Assembly:
The control air damper assembly shall be constructed of heavy gauge galvanized steel with solid shaft rotating in Delrin® bearings. Damper shaft shall be marked on the end to indicate damper position. Damper blade shall incorporate a flexible gasket for tight airflow shutoff and operate over a full 90°.

D.	Controls:
Units shall have pressure-independent pneumatic, electronic, or communicating controls, as specified, capable of maintaining required airflow set points +/-5% of the unit’s capacity at any inlet pressure up to 6-in. wg., when measured at the either inlet duct. 
[LMHDT] In addition, the unit shall be capable of maintaining required airflow setpoints +/-5% of the unit’s capacity at any inlet pressure up to 6-in. wg., when measured at the discharge inlet duct. 
The controllers shall be capable of resetting between factory or field-set maximum and minimum (>350 fpm inlet duct velocity) set points to satisfy the room thermostat demand.
The unit shall be equipped with an amplified flow probe located in each inlet. Air flow for the pressure independent controller (supplied by others) shall be determined with a factory supplied 12 point total pressure, center averaging cross flow sensor, having a magnification resulting in no greater than 2625 fpm @ 1” developed signal.
 [LMHDT] Optionally, a center-averaging 12 point total pressure , center averaging cross flow sensor shall be provided at the unit discharge. The sensor will provide a differential pressure signal having a magnification resulting in no greater than 2625 fpm @ 1” developed signal.

       E: Performance:

1.	The pressure drop through the units shall not exceed scheduled values, including hot water coils. 

2.	Acoustical Requirement

2.1	Unit supplied shall be rated in accordance with ARI 880 certification program at the rated flow rates and pressures. The unit manufacturer shall furnish octave band sound power data for both casing radiated and discharge sound levels with the selected lining and above flow sensor, as tested per ARI Industry Standard 880-98, at the required flow rates and inlet pressures.  Both Discharge and Radiated sound data shall result in room Sound Pressure levels not to exceed those listed below, with a tolerance of + 2 dB in any band for less than 20% of the units, when determined in accordance with ARI 885-98 Appendix E with the following listed assumptions:
2.2	Desired Room Sound Pressure level, dB by Octave Band:
Sound Criteria 		: High Speech Privacy
Octave  Band 		:      2     3     4     5    6    7 
          Room Sound Pressure 	:    57   53   48   43   37   31

2.3	Application Assumptions
Nominal Duct Size = 12.        Nominal Duct Ps = 1.0.

 ----- Discharge Sound Assumptions ------ 
  Sound Power Division based on 2 Power Splits
  5 Ft. of Lined Duct
  5 feet of 8" Flexible duct   
  End Reflection based on a 10" round duct.

Room Absorption based on a  2400 CuFt room,  5 Ft from the source:              
             Octave Band    	:    2    3    4    5    6    7   
     Room Effect, dB       	:    5    7    8    9   10   11

 ------ Radiated Sound Assumptions --------
ARI 885-98 assumes that ceiling located sound sources are not point, but area sources, and the room attenuation is included in the ceiling/space effect, based on the ceiling tile selected.

    Ceiling: ARI 885-98 Type 2, 10 pcf Mineral Tile
              Octave  Band   	:    2      3     4     5     6     7                       
      Total Space Effect   	:   15   17   19   25   30   33

2.4	Maximum Allowable Sound Power 
Based  on the assumptions in section 2.3 above, neither  Radiated or  Discharge Unit sound power shall exceed the following levels at an inlet pressure of 1.0" w.g.:         

            Octave  Band       :    2      3     4     5     6    7    
       Radiated Pwl    ,dB   :   74   71   67   68   67   64
       Discharge Pwl   ,dB  :    79  78   82   90   87   65