Assessing Your Dust & Sizing Ductwork
Whether you are updating a dust collector or designing a new dust collection system, the National Fire Protection Agency (NFPA) now requires that you have a dust control plan as a part of an overall Dust Hazard Analysis (DHA). Per the 2019 revised Standard on the Fundamentals of Combustible Dust – NFPA 652, adding or renovating a dust collection system includes many new criteria. These design requirements will allow you to optimize the effectiveness of your dust collection system.
Evaluating dust collection needs and system design can be viewed as a two part process. Part one starts with sizing your dust collection system ductwork for adequate volume (CFM) and velocity (ft/m) for the type of dust you will be managing. Part two involves calculating the static pressure (SP) of your system to ascertain the proper size of your dust collector and your required system fan power. If you already have a ductwork system and only need to upgrade an existing baghouse system, you will want to calculate the CFM and static resistance from the existing ducting to properly size the fan and baghouse dust collector combination.
Part One: Assessing Your Dust & Sizing Ductwork
Your first step in sizing your system is determining your required capture velocity. This will depend on the type of dust particulate you need to capture, specifically how fast it moves and its volume. The lighter the dust particles are, the lower the velocity will need to be. Conversely, heavy particulate, such as wet dust or metal dust, will require higher velocity. Particles that move slowly can be captured at low velocities, while fast moving particulate will require higher velocities for effective capture. Sizing your dust collection system according to the proper capture velocity is the first step in developing an effective and efficient system.
In our next post, we will look at part two of Basic Dust Collection Design, Selecting Your Dust Collector and Fan.
As an experienced dust collection specialist, we know that not correctly determining any one of these design criteria mentioned in this discussion will significantly impact the performance of a dust collection system. If the task of getting all of the design criteria right for a dust collection system seems overwhelming, allow us to help.