Ventilation
Systems for ventilation and air handling - air change rates, ducts and pressure drops, charts and diagrams and more
Air - Altitude, Density and Specific Volume
Density and the specific volume of air vary with elevation above sea level
Air Change Rate
Calculate air change rates - equations in imperial and SI units
Air Change Rates in typical Rooms and Buildings
Fresh air - or make up air - requirements - recommended air change rates - ACH - for typical rooms and buildings - auditoriums, kitchens, churches and more
Air Curtains and Air Screens
Air curtains or air screens in open doorways are used to keep acceptable indoor comfort in buildings
Air Duct Components and Minor Dynamic Loss Coefficients
Minor loss - pressure or head loss - coefficients for air duct distribution systems components
Air Ducts - Friction Loss Diagram
A major loss diagram for air ducts - Imperial units ranging 10 - 100 000 cfm
Air Ducts - Friction Loss Diagram
Major loss diagram for air ducts - in imperial units ranging 10 000 - 400 000 cfm
Air Ducts - Friction Loss Diagram
Major loss diagram for air ducts - SI units
Air Ducts - Sizing
Air flow and required duct area
Air Ducts - Temperature, Pressure and Friction Loss
Temperature and air pressure influence on air ducts friction loss
Air Ducts - Velocity Diagram
Air flow volume, duct size, velocity and dynamic pressure
Air Ducts Minor Loss Coefficient Diagrams
Minor loss coefficient diagrams for air ductwork, bends, expansions, inlets and outlets - SI units
Air Filter Arrestance and Efficiency
Air filters efficiency and arrestance
Air Flow and Velocity due to Natural Draft
Air flow - volume and velocity - due to stack or flue effect caused by indoor hot and outdoor cold temperature difference
Air Heating Systems
Using air to heat buildings - temperature rise diagram
Air Intakes and Outlets
Ventilation systems - air intakes and outlets - rules of thumbs
Air Return Intakes - Sizes and Capacities
Size and capacity of air return intake
ASHRAE - American Society of Heating, Refrigerating and Air-Conditioning Engineers
ASHRAE Standards
Belt driven Fans - Motor and Fan Speed
Speed of Fan versus Speed of Motor
Belt Transmissions - Length and Speed of Belt
Length and speed of belt and belt gearing
Carbon Dioxide Concentrations in Rooms Occupied with People
The carbon dioxide concentration in a room can indicate air quality and ventilation system efficiency
Carbon Monoxide and Health Effects
Exposure to Carbon Monoxide - CO and the health effects
Circular Ducts - Dimensions
Sizes of circular ventilation air ducts
Classification of Ventilation Dampers
Dampers in ventilation systems may be classified through function, construction or leakage class
Classification of Ventilation Systems
Ventilation systems can be classified by functions, distribution strategies or by ventilation principles
Clean Rooms - Federal Standard 209
Clean rooms are maintained virtually free of contaminants like dust or bacteria
Clean Rooms - ISO Standard 14644
The clean room class limits according ISO Standard 14644-1
Colebrook Equation
Calculate friction loss coefficients in pipes, tubes and ducts
Design of Ventilation Systems
Design procedure for ventilation systems - air flow rates, heat and cooling loads, air shifts according occupants, air supply principles
Duct Sizing - Equal Friction Method
The equal friction method for sizing air ducts is easy and straightforward to use
Duct Velocity
Calculate velocities in circular and rectangular ducts - imperial and SI-units - online calculator
Ducts - Diameter and Cross-Sectional Area
Circular ducts and cross-sectional areas
Ducts - Sheet Metal Gauges
Sheet metal gauges used in ductwork
Ducts Sizing - Velocity Reduction Method
The velocity reduction method can be used for sizing air ducts
Ductwork Seal Classes
Ductwork prone to air leakages
Ductwork Support
Ductwork support and recommended distance between hangers
Energy Equation - Pressure Head Loss in Ducts, Tubes and Pipes
Pressure and head loss in ducts, pipes and tubes
Equivalent Diameter
Convert rectangular and oval duct geometry to a equivalent circular diameter - online calculator with imperial and SI-units
Equivalent Diameter - Rectangular and Circular HVAC Ducts
Equivalent diameter for rectangular and circular ducts - air flows between 100 - 50000 cfm
Evacuation of Air - minimum Capture Velocities to avoid Pollution products transferred to the Room
Capture velocity to avoid pollution products from galvanic baths, spray painting boxes and more contaminating the surrounding room and environment
Exhaust Hoods
Sizing exhaust hoods - air volume flow and capture velocities - online exhaust hood calculator
Exhaust Outlets - Capturing Air Velocities
Capturing air velocity in front of an exhaust outlet - online exhaust outlet velocitycalculator
Fan Affinity Laws
Affinity laws can be used to calculate volume capacity, head or power consumption when speed and wheel diameters are changed
Fan Capacity Diagrams
Pressure, head, air flow volume and fan capacity diagrams
Fan Classification - AMCA
Fan classification established by AMCA
Fan Inlet - Suction Pressure and Air Density
High suction pressure at a fan inlet decreases the density of air - and should be corrected for proper selection of the fan
Fan Motors - Starting Torques
A fan motor must be capable of accelerating the fan wheel to operating speed
Fan Troubleshooting
Guide to troubleshooting fan problems
Fans - Air Temperature and Volume Flow, Pressure Head and Power Consumption
The temperature and density of the air influences on the volume flow, pressure head and power consumption in a fan
Fans - Calculate Air and Brake Horsepower
AHP - Air Horse Power and BHP - Brake Horse Power
Fans - Efficiency and Power Consumption
Power consumption and typical efficiencies of fans
Fans and Capacity Control
Modulating fans and their capacities
Free Area Ventilation
Ventilation required for attic areas
Friction Head Loss in Air Ducts - Online Calculator
Head loss or major loss in air ducts - equations and online calculator for rectangular and circular ducts - Imperial and SI units
Garage Ventilation
Exhaust ventilation from garages and workshops
Gas Vent Termination - Clearance Tolerances
Clearance tolerance per roof slope for gas vent terminations - vent caps
Heat Recovery Efficiency
Classification of heat recovery efficiency - temperature efficiency, moisture efficiency and enthalpy efficiency - online heat exchanger efficiency calculator
Heat-Recovery
Ventilation and heat-recovery calculations, sensible and latent heat -online calculators - imperial units
Heaters and Coolers in Ventilation Systems
The basic equations for heat transfer and the selecting criteria for heaters and coolers in ventilations systems
Humidifiers
Sprayed coils, spinning discs and steam humidifiers
HVAC Dampers - Pressure Loss
Pressure head loss in HVAC damper
HVAC Diagram - Online Drawing
Draw HVAC diagrams - Online with the Google Drive drawing tool
HVAC Ducts - Air Velocities
Ductwork and recommended air velocities
Hydraulic Diameter
Hydraulic diameter of pipes and ducts
Indoor Design Conditions for Industrial Products and Production Processes
Recommended indoor temperature and humidity for some common industrial products and production processes
Indoor Design Temperatures
Recommended indoor temperatures summer and winter
Industrial Environments - Selecting Ventilation System
A quick selection guide for ventilation systems and principles in industrial environments
Mechanical Energy and the Bernoulli Equation
The mechanical energy equation related to energy per unit mass, energy per unit volume and energy per unit weight involving head
Minor Loss Resistance in Ventilation Ducts
Air velocity, minor loss coefficient and minor loss in ventilation duct-works
Odor from Persons - Required Ventilation
Odor and smell - required air ventilation
Odor Intensity from Persons
Room volume, ventilation and odor intensity from persons
Online Air Duct Calculator
Online calculator to compute the friction loss in air ducts
Pollution Concentration in Rooms
Concentration of a pollution in a limited space as a room depends on the amount of polluted material spread in the room, supply of fresh air, outlets positions and construction, principles used for supply and outlet from the space
Pressure Classifications of Duct Systems
Duct systems are commonly divided into three pressure classifications
Pressure Drop in Ventilation Components
Pressure drops in common ventilation system components - like dampers, filters, heaters, coolers
Pumps, Compressors, Blowers and Fans
Comparing pumps, compressors, blowers and fans
Rates of Outdoor Supply Air
Recommended rates of outdoor make up air in some common types of rooms - banks, assembly halls, hotels and many more. Smoking and air supply rates
Rectangular Air Ducts - Velocity Diagram
Velocity diagram for rectangular air ducts - metric units
Rectangular Ducts - Commonly used Dimensions
Metric dimensions of commonly used rectangular air ducts in ventilation systems
Rectangular Ducts - Hydraulic Diameter
Hydraulic diameter for rectangular ducts - metric units
Relative Humidity in Production and Process Environments
Recommended relative humidity in production and process environments - like libraries, breweries, storages and more
Required Air to Remove Moisture
Air flow required to remove vapor production in a room
Required Outdoor Makeup Air
Acceptable indoor air quality
Required Space for Ventilation and Air Conditioning Equipment
Sizes of ventilation and air conditioning rooms according DIN 1946
Room Area per Person
Recommended minimum area per person - common values for calculating indoor climate loads
Roughness & Surface Coefficients
Surface coefficients to calculate flow friction and major pressure loss - surfaces like concrete, galvanized steel, corroded steel and more
Scrubber Basics
In a wet scrubber process air is drawn through a mist of water made by spray nozzles, then through separators where water droplets with dust and particles are removed
Selecting Ventilation System in Comfort Environments
A quick selection guide of ventilation system in comfort environments
Sizing Circular Ducts
A rough guide to maximum air volume capacity of circular ducts in comfort, industrial and high speed ventilation systems
Spiral Duct Elbows - Weights
Ductwork - weights of galvanized round spiral elbows
Spiral Ducts - Dimensions
Standard dimensions of spiral ducts - Imperial units
Stack or Flue Effect
The stack or flue effect occurs when the outdoor temperature is lower than indoor temperature
STP - Standard Temperature and Pressure & NTP - Normal Temperature and Pressure
The definition of STP - Standard Temperature and Pressure and NTP - Normal Temperature and Pressure
Types of Fans
Axial and propeller fans, centrifugal (radial) fans, mixed flow fans and cross flow fans
Types of Fans - Capacity Ranges
Centrifugal, axial and propeller fans and their capacity ranges
Typical Air Duct Velocities
Typical air duct velocities in applications like ventilation systems or compressed air systems
U-Tube Manometer
The inclined and vertical u-tube manometers are inexpensive and common in the differential pressure measurement with flow meters like pitot tubes, orifices and nozzles
Velocity Classification of Ventilation Ducts
Recommended air velocities in ventilation ducts
Ventilation Efficiency
The efficiency of a ventilation system may be related to temperature and/or pollution concentrations
Ventilation Filters
Classification of air filters used in ventilation systems
Ventilation Principles
Some commonly used ventilation principles - short cut, mixed air, displacement and piston principle
