Manual T - Air Distribution Basics
ACCA’s Manual T: Air Distribution Basics for Residential and Small Commercial Buildings provides detailed information on how to select, sizing, and locate constant volume supply out-lets and return inlets. Floor, low-side wall, high-side wall, and ceiling out-lets are also discussed.
Additionally, Manual T replaces all current and previous editions of ACCA Manual E: Room Air Distribution Considerations. Manual T contains all of the information previously provided in Manual E, with a considerable amount of additional information.
PURCHASE MANUAL
Manual T is divided into twelve sections with an additional two appendices for supplementary information.
Section 1 - What Makes People Comfortable
Section 1 begins with the importance of proper air terminal sizing and selection procedures and their relationship with how various factors affect human comfort.
- Minimum Amount of Air Required for Survival
- Amount of Air Required for Comfort
- Metabolic Rate
- Heat Transfer to the Surrounding
- Effect of Surrounding Temperature
- Building Envelopes Affects Human Comfort
- Mean Radiant Temperature
- Effect of Winter Humidification
- Effect of Velocity
- Natural Convection
- ASHRAE Comfort Chart
- Temperature Gradients
Section 2 - Air Distribution Concepts and Terminology
Section 2 goes over the terminology and design concepts associated with Air Distribution.
- General Categories of Terminal Devices
- Types of Ceiling Diffusers
- Types of Floor Diffusers
- Primary Air and Secondary Air
- Throw
- Drop
- Rise
- Surface Effect
- Spread
- Primary Air Pattern
- Total Air Pattern
- Entrained Air
- Stagnate (or Stratified) Zone
- Vertical Temperature Gradient
- Gross Area
- Free Area
- Face Velocity
- Core Velocity
- Velocity / Flow-Rate Equation
Section 3 - High Sidewall Terminals
Section 3 goes over expected air patterns when working with high-sidewall terminals.
- Location
- Primary Air Pattern
- Entrance Condition Affects the Air Pattern
- Total Air Pattern
- Stratification
- Secondary Air Pattern
- Use Vanes to Control Air Pattern
- Characteristics of High Sidewall Registers
- Location of Returns
Section 4 - Ceiling Diffusers
Section 4 goes over expected air patterns when working with ceiling terminals.
- Primary Air Pattern, Radial Discharge
- Primary Air Pattern, Directional Discharge
- Primary Air Pattern, Vertical Discharge
- Entrance Conditions Affect the Air Pattern
- Total Air Pattern, Horizontal Discharge
- Total Air Pattern, Vertical Discharge
- Stratification, Horizontal Discharge
- Stratification, (Vertical Discharge Diffusers)
- Characteristics of Horizontal Discharge Outlets
- Characteristics of Vertical Discharge Outlets
- Location of Returns
Section 5 - Floor and Low Sidewall Outlets
Section 5 goes over expected air patterns when working with floor-mounted diffusers, low sidewall diffusers, floor registers, and low sidewall registers.
- Primary Air Pattern, Vertical Diffuser
- Primary Air Pattern, Vertical Registers
- Primary Air Pattern, for Horizontal Discharge
- Entrance Conditions Affect the Air Pattern
- Total Air Pattern, (Vertical Discharge Diffusers)
- Total Air Pattern, (Vertical Discharge Registers)
- Total Air Pattern, (Horizontal Discharge Outlets)
- Basement Heating
- Stratification, (Vertical Discharge Diffusers)
- Stratification, (Vertical Discharge Registers)
- Stratification, (Horizontal Discharge Outlets)
- Floor and Low Sidewall Outlet Characteristics
- Location of Returns
Section 6 - Pressure Loss Characteristics of Supply Outlets
Section 6 details the nature and principles of pressure loss through supply outlets.
- Inches of Water
- Static Pressure
- Total Pressure
- Velocity Pressure
- Static Regain
- Pressure Loss with Constant Velocity
- Pressure Loss with Changing Velocity
- Pressure Loss of Supply Outlets
- Accessory Pressure Loss
- Optimum Outlet-Fitting Geometry
Section 7 - Performance of Return Inlets
Section 7 discusses the performance and importance of Return Inlets.
- Types of Return Inlets
- Negligible Effect on Room Air Patterns
- Guidelines for Locating Returns
Section 8 - Pressure Loss Characteristics of Return Inlets
Section 8 discusses the pressure loss characteristics of Return Inlets.
- Inlet Pressure Loss
- Pressure Loss is Affected by Inlet Geometry
Section 9 - Sound Considerations
Section 9 details the sound considerations when working with air distribution systems.
- Frequency
- Sound Pressure
- Sound Power
- Frequency Spectrum
- Loudness Chart
- Noise Criteria Rating
- Published NC Ratings
- Acceptable NC for Various Applications
- Face Velocity Guidelines
- Catalog Velocity Recommendations
- Installations Details Affect Noise Levels
- Integral Dampers Generate Noise
- Attenuations Generation
- Equipment Near the Occupied Space
Section 10 - Selecting Supply Outlets
Section 10 covers the selection process when choosing a supply outlet.
- Objectives
- Location
- Approximate Air Terminal CFM
- Selection Procedure
- Effect of Fan Operation
- Noise Criteria
- Manufacturer’s Data
- Floor, Baseboard and Low Sidewall Outlets
- Example: Floor on Baseboard Outlet Selection
- Ceiling Diffusers
- Example: Non Directional Ceiling Diffuser
- Example: Direction Ceiling Diffuser
- High Sidewall Outlets
- Example: High Sidewall Outlet Selection
Section 11 - Selecting Return Inlets
Section 11 goes over the selection process when choosing return inlets.
- Style and Location
- Size
- Pressure Drop
- Transfer Grilles
- Filter Gilles
- Residential Example
- Commercial Example
- Transfer Grille Example
Section 12 - Balancing and Measuring Air Flow
Section 12 goes over the process of successfully balancing and measuring a system’s airflow.
- Balancing Procedures
- Area Factor
Appendix 1 - Manufacturer’s Application Data
Appendix 2 - Summary of Tables, Charts and Equations