Exhaust Fan and Blower System Evaluation

Purpose

• To define the operating rating of an existing exhaust fan or blower system
• To identify causes for deficient fan performance, excessive dynamic
  vibration, or high noise levels
• To evaluate the suitability of the fan type, construction and arrangement to the application

Procedure

• Measure gas stream volume, density, temperature, suction and discharge pressures, obtain motor brake horsepower
• Evaluate fan inlet and outlet conditions for velocity pressure profile,
  look for flow disturbances that can cause deficient fan performance
• Define system curve conditions and superimpose onto fan characteristic curve in order to evaluate possible fan - system interactions that could lead to deficient fan performance
• Evaluate gas conditioning, scrubbing or filtration equipment operation in terms of their impact on fan performance, especially in light of pressure drop variances or automatic volume flow adjustments
• Examine any flow control schemes that may be present for stable fan operation throughout the control range required
• Confirm the suitability of the fan design employed for the duty, including wheel geometry, materials of construction, volume control system, arrangement etc.

Report

• Provide a written report summarizing the existing fan performance
  and comparing it to the design intent
• Provide a copy of the manufacturers fan curve at the actual measured rating with the operating point indicated on the curve
• Give specific recommendations on how best to correct deficient performance through duct or fan modifications, system operating philosophy revisions, or a combination of these