What is dilution ventilation?

Dilution ventilation supplies and exhausts large amounts of air to and from an area or building. It usually involves large exhaust fans placed in the walls or roof of a building. Dilution ventilation controls pollutants generated at a worksite by ventilating the entire workplace.

What is natural dilution ventilation?

Natural Dilution Ventilation Dilution ventilation adds new fresh air to an area and can be accomplished by non-mechanical means such as opening windows and doors, or mechanical means such as wall and roof exhaust fans. Weld out of the plume. Use a tight fitting welding helmet to shield you from the plume.

How do you calculate ventilation rate in a confined space?

It can be calculated by multiplying the volume of gas, either inhaled or exhaled, during a breath (the tidal volume) by the breathing rate [e.g., 0.4 liter (or 0.4L) × 15 breaths/min = 6L/min].

Is there a standard used for general ventilation?

A general ventilation system is one that exchanges stale indoor air for air from outdoors. However, a general ventilation systems cannot be relied upon to remove air impurities. A simple air conditioner, fan or open window or door are all examples of general ventilation systems.

How does ventilation reduce the concentration of contaminants?

Dilution (or general) ventilation reduces the concentration of the contaminant by mixing the contaminated air with clean, uncontaminated air. Local exhaust ventilation captures contaminates at or very near the source and exhausts them outside.

How is dilution ventilation used in heat control?

Dilution Ventilation and Heat Control Problem: Methyl Chloride evaporates from a tank at a rate of 0.24 cfm. Find the required air flow Q to maintain the exposure level below 200 ppm. Solution: Q’ = (403 * 106* SG * ER) / (MW * C) where Q’ is effective flow rate in cfm, SG is specific gravity, ER is emission rate in pints/min,

How is local exhaust used to control air contaminants?

Local exhaust system is used to control air contaminants by trapping them at or near the source, in contrast to dilution ventilation which lets the contaminant spread throughout the workplace.

How to calculate dilution ventilation for fire explosion hazard?

Problem: Calculate the dilution ventilation for fire explosion hazard (C=10) for 1 pint of xylol given LEL=2%, MW=106, B=0.7, and Sp.Gr.=0.88. Solution: Q’ = (403 * 100 * SG * ER) / (MW * LEL * B) where Q’ is effective flow rate in cfm, SG is specific gravity, ER is emission rate in pints/min]