Search Results for: air changes per hour

Seminar 57 : The History of the Use of Air Changes per Hour in HVAC Codes, Standards and Guidelines

Seminars

Atria Smoke Exhaust: 3 Approaches to Replacement Air Delivery

Journal

Smoke exhaust requirements for atria, as mandated in recent building codes can include exceptionally high exhaust rates. Previous guidelines for atrium smoke exhaust system volume (often given as 6 air changes per hour) are inadequate3 in many cases as shown by sophisticated computer models and actual fire experience.

Impact of New Ventilation Guidance, Standard 241 on Energy Costs, Carbon Emissions: Why Equivalent Clean Airflow Doesn’t Have to Be Expensive

Journal

This column is a detailed review of simulation results that looked at the energy and carbon impacts of outdoor air ventilation versus hybrid strategies that combine outdoor air ventilation with air cleaning to meet the newly established CDC target (air changes per hour [ach]) and ASHRAE Standard 241, Control of Infectious Aerosols, equivalent clean airflow (ECAi) for commercial, residential and health-care space types.

Seminar 52 -- Without Ventilation Effectiveness, Air Change per Hour Is Just a Number

Conference Proceeding

Seminar 52 -- Without Ventilation Effectiveness, Air Change per Hour Is Just a Number

Seminar 52 -- Without Ventilation Effectiveness, Air Change per Hour Is Just a Number

Conference Proceeding

Seminar 52 -- Without Ventilation Effectiveness, Air Change per Hour Is Just a Number

CFD Analysis for Design Optimization of a Pharmaceutical Cleanroom

Journal

The computational fluid dynamics (CFD) study in this article evaluates the impact of air changes per hour (ach) and the locations of supply diffusers on the airflow patterns and the resulting distribution of particles in the critical zone of a pharmaceutical cleanroom, which is used for manufacturing sterile and nonsterile drugs and medical products and often require a high level of cleanliness to maintain an aseptic environment.

Ventilation Heat Recovery For Laboratories

Journal

Laboratories typically require 100% outside air at high ventilation rates - between 6 and 12 air changes per hour - primarily for safety reasons. The heating and cooling energy needed to condition this air, as well as the fan energy needed to move it, often is five times greater than the amount of energy used in most offices for these same purposes. Energy recovery can substantially reduce the mechanical heating and cooling requirements associated with conditioning ventilation air in most laboratories. As a result of the lower peak heating and cooling requirements with energy recovery, heating and cooling systems can be downsized.

Transportation FAQ

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Improved Ventilation System for Removal of Airborne Contamination in Airborne Infectious Isolation Rooms

Learn more about Improved Ventilation System for Removal of Airborne Contamination in Airborne Infectious Isolation Rooms at ashrae.org