1. Terminal Unit Overview
T.U. Overview
Terminal Unit Overview
Evan Himelstein, P.Eng.
Application Engineering
Price Industries
October 11, 2004

2. Agenda Terminal Unit types and characteristics Pressure Definitions
T.U. Overview
Agenda
Terminal Unit types and characteristics
Single Duct Terminals
LGF – Flow Measurement
LGE - Exhaust Terminal
LGS - Supply Terminal
Construction & tube construction
Flow Sensors (SP200 & Orifice Ring)
Venturi Air Valve
Pressure Definitions
Terminal Unit Sound / Acoustics
Hot Water Coils
General Pitfalls
Questions
On the agenda today, we will be covering the terminal unit types and characteristics. This will be split up between single duct blade terminals and venturi air valves. We will then move along to pressure definitions, terminal unit sound and acoustics. Finally we will cover off hot water coils and general pitfalls people end up having. Finally we will have time for questions.

3. Terminal Unit Types Single duct terminal units
T.U. Overview
Terminal Unit Types
Single duct terminal units
Controller type – Siemens LGS
Mechanical type
Control / Exhaust Valves
Siemens LGE
Venturi Air Valves
Dual Duct Terminals
Fan Powered Terminals
Constant Volume / Series Flow
Variable Volume / Parallel Flow
Induction Terminal Units
Retrofit Terminal Units
Flow Measurement Devices
Siemens LGF
Discussed Today
Discussed Today
Discussed Today
There are many types of terminals. Not all of which are relevant for this discussion. For information on other terminal types you can go to the Price website. The terminals that will be discussed today are the Siemens LGS, LGE and venturi valves.
For more information on terminal unit types not covered see the Price website,
Discussed Today

4. Flow Measuring Devices Siemens LGF
Laboratory Air Flow Station
Not really a terminal unit, but...
Galvanized Steel with optional 316L Stainless Steel Continuously Welded Construction
Orifice Ring Sensor Available in sizes 4, 6, 8, 10, 12, 14, 16, 18, 20, 22
SP200 Sensor Available in sizes 6, 8, 10, 12, 14, 16
New shorter version (8”)

5. Single Duct - Exhaust Terminals Siemens LGE
T.U. Overview
Single Duct - Exhaust Terminals Siemens LGE
Basic unit includes
Damper
Flow Sensor
SP200
Orifice
Duct Type
Galvanized
Stainless Steel
Teflon Coated
Model LGH discontinued

6. Single Duct Terminals Siemens LGS
T.U. Overview
Single Duct Terminals Siemens LGS
Basic unit includes
Damper
Flow Sensor (SP200)
Heating Coil (optional)
Attenuator (optional)
Operation
Varies air volume to space
Monitors air flow sensor
Pressure independent
Single duct terminals – most common and economical. Reliable & simple operation. Includes damper, flow sensor, heating coils, and attenuator. Operation generally varies supply air volume to space based on temperature or pressure. Unit is pressure independent as the controls monitors the airflow sensor.

7. Pressure Dependent vs Independent
T.U. Overview
Pressure Dependent vs Independent
Pressure Dependent
Flow rate varies with system inlet pressure fluctuations.
Flow rate dependent on inlet pressure and damper position
Pressure Independent
Flow rate is constant regardless of inlet pressure fluctuations
Achieved by adding a flow sensor and flow controller
Controller maintains a preset flow through the inlet by modulating the damper in response to the flow signal.
What is the difference between a pressure dependent and pressure independent boxes.

8. Single Duct Terminals Options Price can support Specials!
T.U. Overview
Single Duct Terminals
Options
Hot Water Coils
1, 2, 3 or 4 rows
Standard access door for inspection & cleaning
Sound Attenuators
3 or 5 foot
Price can support Specials!

9. Single Duct Terminals Liner
T.U. Overview
Single Duct Terminals Liner
This system integrates an engineered polymer foam which provides excellent insulating characteristics.
The foam edges are self sealing due to the material’s composition.
Material has a water vapor permeability of 0.0%, and will not initiate mold growth.

10. Siemen’s Specific Features
T.U. Overview
Siemen’s Specific Features
Standard FF (Fiber Free) Liner
Access door in LGS casing not in water coil
Sensor tubes in brass fittings not rubber grommets
Standard Extra low leakage construction
Individually packaged – 2x Weight Cardboard Cartons
Special Siemens Labeling

11. LGS Casing Leakage Unit in CFM in % of Max Flow Size 1.00” 3.00” 6.00”
T.U. Overview
LGS Casing Leakage
Unit
in CFM
in % of Max Flow
Size
1.00”
3.00”
6.00” 4 1 2 3
0.40%
0.90%
1.30% 6
0.30%
0.60% 8
0.20%
0.70% 10
0.50% 12
0.10% 14 5 16 7 18

12. LGS Damper Leakage Unit Size in CFM % of Maximum Flow 1.50” 3.00”
T.U. Overview
LGS Damper Leakage
Unit
Size
in CFM
% of Maximum Flow
1.50”
3.00”
6.00” 4 5 6
1.78%
2.22%
2.67% 11
0.89%
1.33%
2.44% 8 7 10
0.63%
0.88%
1.25%
0.44%
0.52%
0.74% 12 19
0.38%
0.57%
0.90% 14 16
0.20%
0.33%
0.53% 13 21 38
0.95% 18 98
154
305
1.23%
1.93%
3.81%

13. Single Duct Damper Construction
T.U. Overview
Single Duct Damper Construction
Toggle-Lock Sandwich Construction
2 pieces of 22 gauge galvanized sheet-metal riveted together
No welding required
Zinc anti-rust protection is not ruined
No heat distortion of blade (leakage)
** Request from Jerry 2 or 3 damper blades **

14. Single Duct Damper Seal
Polyurethane Gasket
Flexible material provides excellent seal
Does not dry out and crack with age
1.5 million cycle operational test resulted in no measurable change in leakage rate
Equates to 100 full damper cycles per day, ( complete open and closures) for 42 years
Gasket

15. Single Duct Damper Shaft
T.U. Overview
Single Duct Damper Shaft
Solid Steel Shaft
Anti-rust Nickel Plating
Damper position indicator on end of shaft
Self-lubricating, tight-fit, low-leak bearings
Much stronger than plastic or aluminum shafts
Retaining-Clips for accurate centering

16. Single Duct Damper Shaft Bearings
T.U. Overview
Single Duct Damper Shaft Bearings
Set of three bearings
Made from high density Polyethylene
Will operate to inlet static pressures up to 6 inches W.G. with minimal leakage
Only manufacture to use 3 bearings
Tested to 1.25 million cycles
Equates to 100 full damper cycles per day, ( complete open and closures) for 35 years

17. Single Duct Inlet Tube Construction
T.U. Overview
Single Duct Inlet Tube Construction
Rolled Bead
Stronger
More Round
Stop for hard duct
Seam
Riveted connection
Sealed with caulk
Long
Eliminates need for straight duct before the inlet
Cross flow sensors will be demoed and are not covered in this presentation.

18. Valve Sizing Size Valve based on maximum and minimum airflow
T.U. Overview
Valve Sizing
Size Valve based on maximum and minimum airflow
With Maximum Flow review
Sound
Pressure Drop
Flexibility
Cost
With Minimum Flow
Control Accuracy
Type of Controls
Select above 400 FPM duct velocity

19. SP200 Air Volume Sensor The “Heart” of VAV Control
T.U. Overview
SP200 Air Volume Sensor
The “Heart” of VAV Control
Velocity Sensor performance is a function of:
Cross Sectional Area
Number and Pattern of Sensing Ports
Amplification Factor
Center averaging capabilities

20. Air Volume Sensing
T.U. Overview
Pt = Total Pressure – Combination of Static and Velocity
Ps = Static Pressure – The Pressure in the duct pressing in all directions
Pv = Velocity Pressure – The pressure in the duct due to the velocity of the air (NOT DIRECTLY MEASURABLE)
Pt = Ps + Pv OR Pt - Ps = Pv

21. Sensible Sampling Port Locations Total-Pressure Ports Static-Pressure
T.U. Overview
Sensible Sampling
Port Locations
Total-Pressure Ports
Static-Pressure
Ports
Price’s SP-200 has strategically-located
Total Pressure ports,
based on extensive
lab-tested fine-tuning.
Better than the “duct-
traverse” method.

22. Unbiased Representation
T.U. Overview
Unbiased Representation
Center-Averaging Collection Chamber
Pressure-averaging at the center of the SP-200 gives
assurance that all four of
the quadrants’ velocities have equal representation.

23. Amplification and Error
T.U. Overview
Amplification and Error
Reliable Accuracy at Low Airflows
Most controls require at least 0.02”-0.03”w.g. sensor-output signal for reliable operation
The SP-200 flow sensor provides 0.025”w.g. at 400 FPM,
Sensors w/ low gain & poorly-averaged (worst case) have a safe low-end of 700 to 800 FPM

24. Flow Sensing Problems Inlet Condition Problems No Velocity (turbulent)
T.U. Overview
Flow Sensing Problems
No Velocity
(turbulent)
Inlet Condition Problems
90 deg.
Elbow
High Velocity

25. Orifice Plate Air Volume Sensing
T.U. Overview
Orifice Plate Air Volume Sensing
Orifice Ring Sensing
4 Sensing points
Non Clogging design
Very Robust
Measures static pressure differential
Airflow = k * (ΔP)½
Watch for inlet conditions

26. Venturi Air Valves Mechanically pressure independent
T.U. Overview
Venturi Air Valves
Mechanically pressure independent
Requires a minimum static pressure ( 0.3” L.P., 0.6” M.P.)
Consists of
Cone
Springs
Aerodynamic shape
Orifice Ring (Flow sensing)
Price only supplies accessories for Venturi Air Valves

27. Venturi Air Valve Flow ~ Area*Sqrt(dP)
T.U. Overview
Venturi Air Valve
Flow ~ Area*Sqrt(dP)
Spring inside cone expands or compresses to compensate for changes in pressure across valve.
At low pressure drop, spring pushes cone out, increasing flow area.
At high pressure drop, cone compresses spring, decreasing flow area.
Change diagrams to use Siemens pictures (symmetrical venturi shape)

28. Venturi Air Valve Pressure & Flow Variation
T.U. Overview
Venturi Air Valve Pressure & Flow Variation

29. Venturi Air Valves Accessories Sound Attenuators Hot Water Coils
T.U. Overview
Venturi Air Valves
Accessories
Sound Attenuators
3 or 5 foot
Hot Water Coils
1 Row
2 Row
3 & 4 Row optional
Materials
Standard: aluminum body & cone, teflon-coated stainless steel cone rod, brackets, linkage and control arm
Heresite-coated body and cone available for corrosive exhaust applications

30. Pressure What do all these catalog terms mean?
T.U. Overview
Pressure
What do all these catalog terms mean?
Minimum operating pressure
Inlet Static pressure
Downstream Static Pressure
Differential Static Pressure (ΔPs)

31. Minimum Operating Pressure
T.U. Overview
Minimum Operating Pressure
Static Pressure Drop or Loss
Wide Open Damper Position
Minimum Operating Pressure
Pressure Loss of Terminal and Accessories

32. T.U. Overview
Inlet Static Pressure
Pressure From Inlet to Atmosphere

33. Downstream Static Pressure
T.U. Overview
Downstream Static Pressure
Pressure from Downstream of Terminal Unit to Atmosphere

34. Differential Static Pressure
T.U. Overview
Differential Static Pressure
Pressure Drop Across Terminal Only
Not Inlet Static Pressure
ΔPS = Inlet SP-Downstream SP

35. Sound Standards ARI 880-98 Air Terminal Test Standard
T.U. Overview
Sound Standards
ARI Air Terminal Test Standard
ASHRAE Air Terminal Test Method
ARI Application Standard
ADC 1062 – Obsolete and replaced with ARI Standards

36. Testing Standards ASHRAE Standard 130-1996 ARI Standard 880-98
T.U. Overview
Testing Standards
ASHRAE Standard
Specifies the methods and procedures for performance testing of constant and variable volume air terminal units.
ARI Standard
Determines the requirements for testing and rating air terminals
References ASHRAE Standard
Establishes the procedures, rating points and tolerances for conformance to the ARI 880 Certification Program.

37. T.U. Overview
Catalog Sound Data
Due to the vast scale of sound pressures over the normal range of human hearing, the Log of the actual value is used. (Makes scale smaller)
Reference power is Watts
The reference pressure is MicroBars.
dB are measured with respect to frequency
The frequencies are grouped into ‘octave bands’

38. T.U. Overview
Octave Band
Octave band 2 through 7 usually associated with terminal units
Refers to centerline frequencies of 125 to 4000 Hz
Octave Band
Mid Frequency Hz 2
125 3
250 4
500 5
1000 6
2000 7
4000

39. T.U. Overview
Noise Sources

40. T.U. Overview
Catalogue Sound Data
Certified in accordance with ARI 880 Certification Program

41. T.U. Overview
ARI Certification
Price units are ARI Certified, Siemens working on there Application for Certification.
Test data submitted to ARI
Data listed in ARI Directory (and website)
Yearly Random Tests
Tested at an Independent Lab
Test Failures are Published and Penalized
Price has had a 100% Test Success Rates since 1994

42. T.U. Overview
Noise Criteria (NC)
The NC value is the most commonly specified sound criteria for diffusers and terminal equipment.
Standard curves used to describe a spectrum of measure sound pressure levels with a single number.
Sound pressure is not cataloged.
Must be calculated from Sound Power (in catalog) and taking deductions (from ARI Standard 885)

43. T.U. Overview
NC Curves

44. Sound Warning Compare NC values between manufacturers carefully!
T.U. Overview
Sound Warning
Compare NC values between manufacturers carefully!
Attenuation allowances between manufacturers are not always the same.
Engineers do not specify this correctly
Need to educate engineer on ARI Standard 885
Prudent for labs to examine attenuation allowances since they are usually harder, i.e. noisier than the typical office space.

45. Application Standards
T.U. Overview
Application Standards
ARI Standard
“Procedure for Estimating Occupied Space Sound Levels in the Application of Air Terminals and Air Outlets.”
Provides methods to use ARI Standard 880 sound ratings to estimate the sound levels which will occur in the conditioned, occupied space.
Appendix E created with “Typical Attenuation Values” for offices

46. Hot Water Coil General Construction
T.U. Overview
Hot Water Coil General Construction
½” Copper Tubes
Aluminum Fins for Heat Transfer
Access door for cleaning and inspection
Right or left handed connections

47. Water Coil Construction Features
T.U. Overview
Water Coil Construction Features
Construction features that have the most effect on performance …
Fin Height / Fin Length (Coil Area)
Number of Rows
Fin Spacing (FPI)
10 FPI is standard, 8 and 12 are optional

48. Water Coil Application Variables
T.U. Overview
Water Coil Application Variables
Variable that have the most effect on performance …
Target Variable – Coil Capacity - BTU’s / Hr (MBH)
Airflow – CFM (cubic feet per minute)
Water Flow – GPM (gallons per minute)
Entering Air Temperature – EAT (°F)
Entering H2O Temperature – EWT (°F)

49. Water Coils Other Important Factors
T.U. Overview
Water Coils Other Important Factors
Water Pressure Drop (ft.wg.)
Can affect pump / pipe / valve sizing
Depends largely on Number of Circuits
Air Pressure Drop (in.wg.)
Effects central fan sizing
Effects units fan capacity
Leaving Water Temperature
Can cause problems in Hydronic System

50. Water Coils Factors Water Velocity
T.U. Overview
Water Coils Factors Water Velocity
Laminar flow in coils produces very large MBH variations from small changes in Flow (GPM).
Fully turbulent flow variations produce small MBH changes, high head loss, and tube pitting.
Transitional flow is desirable, which is between the laminar and turbulent regions.
Transitional flow range occurs between 0.5 and 8 FPS depending on many factors.

51. Water Coil Calculation Givens
T.U. Overview
Water Coil Calculation Givens
CFM or Airflow rates
More air = more heat
But not PROPORTIONAL
Entering Water & Air Temperatures
EWT has significant impact on capacity
EAT can be a mix of return, supply and fan air
Standard coil configuration
FPI, # of circuits and rows, find type, metal thickness.

52. Water Coil How variables inter-relate
T.U. Overview
Water Coil How variables inter-relate
As the GPM Increases
Heat transfer & leaving air temp increases
Leaving water temperature increases
Water pressure drop increases (fast!)
As the number of rows increase
Air pressure drop and leaving air temp increases
Water Pressure drop might increase
Leaving water temperature decreases

53. Water Coils Prioritization of Parameters
T.U. Overview
Water Coils Prioritization of Parameters
Coil must meet or exceed true MBH load
If a little low on capacity, call engineer or check
Double check MBH using Air delta T calcs
ATR (°F) = 927 x MBH / CFM
Do not exceed the sum of specified GPMS’s
OK for a given coil to vary
Total cannot be higher, or pump & pipe change
Keep the head below the max scheduled
Could increase the equipment requirements

54. Water Coils Hardware Related Choices
T.U. Overview
Water Coils Hardware Related Choices
Number of Coil Rows
Extra expense and air pressure drop
Sometimes specified by the Engineer
Check Spec.
Overall Terminal or Coil Size
Larger boxes have more coil area = more potential capacity
Can create control problems

55. Terminal Selection Pitfalls
T.U. Overview
Terminal Selection Pitfalls
Smaller terminals for lower discharge noise
Don’t oversize
Size 12 and over locate over non critical area

56. Terminal Unit Suggestions
T.U. Overview
Terminal Unit Suggestions
Do not over pressurize ductwork
Increases Sound & Noise
Use lined duct (in non-critical areas)
Reduces high frequency noise
Do not have any diffuser closer than 4’ from the outlet of the terminal unit
Limit velocity in ductwork to 1000 fpm
Best sound performance.

57. TU Noise - Troubleshooting
T.U. Overview
TU Noise - Troubleshooting
Noise from a terminal can be due to a variety of conditions, and sometimes can be difficult to eliminate.
First steps is to isolate the type, source and direction of the noise
If noise is heard at the air outlet – discharge noise
If noise is heard through the ceiling – radiated noise

58. Discharge Noise Usually caused by Can be reduced by High Static
T.U. Overview
Discharge Noise
Usually caused by
High Static
Little or no internal duct lining downstream of the terminal.
Sometimes air outlet dynamics (damper?)
Can be reduced by
Reducing flow
Increasing air outlet size
Reducing inlet static pressure
Adding attenuation materials

59. T.U. Overview
Questions & Comments??