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ED&G 100 Design Project. Fume Hood Face Velocity Control Spring 2004. Tonight’s Agenda. Functionality of a fume hood Types of fume hoods Laboratory Room Airflow Control Fume hood face velocity calculation Fume hood testing methods Safety Concerns Design Project Recap Questions.
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ED&G 100 Design Project • Fume Hood Face • Velocity Control • Spring 2004
Tonight’s Agenda • Functionality of a fume hood • Types of fume hoods • Laboratory Room Airflow Control • Fume hood face velocity calculation • Fume hood testing methods • Safety Concerns • Design Project Recap • Questions
Fume Hoods • What is a fume hood? • How does a fume hood work?
Fume Hood Control Constant Air Volume Fume Hood
Fume Hood Control Variable Air Volume Fume Hood
Fume Hood Control Fume Hood Cost Savings Example • 6 foot wide fume hood • 1250 CFM maximum exhaust airflow • Cost to operate: • Constant Volume Hood - $3750 - $6250 • Variable Volume Hood - $1500 - $2500
Fume Hood Sash • What is a sash? • What are the different configurations for the sash? • What happens when a sash is moved?
Fume Hood Face Velocity • What is face velocity? • How is face velocity calculated?
Average Value for Face Velocity • What is the average value for face velocity? • What happens if the face velocity is above or below 100 (ft/min)?
ACGIH NIOSH ANSI (Standard Z9.5-1992) NFPA OSHA NIH SEFA 80 to 100 fpm 100 to 150 fpm 80 to 120 fpm 80 to 120 fpm 60 to 100 fpm 100 fpm 100 fpm Average Face Velocity Recommendations
Fume Hood Testing – ASHRAE 110 Standard • Measurements of Face Velocity • Air Flow Visualization Test (Smoke Test) • Tracer Gas Containment Test
Laboratory Safety Concerns • Fume hoods are the primary protection of the lab occupant • Labs can contain biomedical wastes, toxic or hazardous chemicals, explosive substances, radioactive isotopes, etc.
Some Safety Guidelines and Regulations • ANSI/AIHA Z9.5, “Laboratory Ventilation” • OSHA Laboratory Standard 29CFR 1910.1450 • NFPA 45 • ASHRAE TC 9-10 • Public Works Canada MD 15128 • FDA Validation Protocols • Local Building Codes
Design Project Recap • Goal: Design a method for calculating the open fume hood face area (sash opening) and maintaining a safe face air velocity at all times and with all sash positions. • Critical Design Requirements: • A materials cost goal <$2000. • Adaptable for various fume hood and sash configurations. • Must be “maintenance-friendly” – must be able to access equipment for preventative care, problems, etc. • Must be able to be installed in less than 45-55 minutes. • Must not interfere in any way with the day-to-day operations of the fume hood user. • Must be stable, repeatable, and accurate to be able to be used at FDA-regulated sites (e.g. pharmaceuticals, etc.) • Must not contribute to overall laboratory noise (both from the fume hood exhaust airflow control system and the fume hood sash sensing system).
Questions? • Good luck on your design projects!