Views: 0 Author: Site Editor Publish Time: 2025-07-25 Origin: Site
Proper sealing between fume hoods and ventilation ducts is essential to prevent leaks, ensure safety, and maintain efficient airflow in laboratory environments. Below are critical sealing requirements to adhere to during installation and maintenance.
Choosing the right sealing materials ensures durability and compatibility with the operating environment.
Chemical Resistance: Seals must resist corrosion from chemicals used in the fume hood. Materials like silicone or fluoropolymer-based sealants are often preferred for their inertness.
Temperature Tolerance: The sealant should withstand the temperature range of the exhaust air, including potential heat from equipment or chemical reactions.
Expansion Compatibility: The coefficient of thermal expansion of the sealant should match that of the fume hood and duct materials to prevent cracking or separation under temperature fluctuations.
Correct installation techniques guarantee the effectiveness of the sealing system.
Surface Preparation: Clean and dry the connection surfaces thoroughly before applying sealants to ensure proper adhesion. Remove any grease, dust, or old sealant residues.
Uniform Application: Apply sealant evenly along the joint to avoid gaps or thin spots. For flanged connections, ensure the sealant fills the entire gap between the flange faces.
Curing Time: Allow the sealant to cure fully before subjecting the system to pressure or airflow. Follow the manufacturer’s recommended curing time and conditions.
Verifying the integrity of the seal is crucial to prevent hazardous leaks.
Positive Pressure Testing: Introduce air into the duct system at a pressure higher than normal operating conditions and check for leaks using soapy water or electronic leak detectors.
Negative Pressure Testing: Alternatively, create a vacuum in the system and monitor for pressure drops that indicate leaks. This method is particularly useful for fume hoods handling toxic or flammable gases.
Re-Testing After Modifications: Any changes to the system, such as duct reconfiguration or fume hood relocation, require re-testing to ensure the seals remain intact.
Regular maintenance extends the lifespan of seals and ensures ongoing safety.
Visual Inspections: Schedule periodic checks for signs of seal degradation, such as cracking, peeling, or discoloration. Pay special attention to areas exposed to high temperatures or chemicals.
Reapplication Schedule: Replace sealants according to the manufacturer’s guidelines or when inspections reveal significant wear. Do not wait for leaks to occur before taking action.
Documentation: Keep records of sealant types, application dates, and inspection results to track maintenance history and anticipate future needs.
By adhering to these sealing requirements, laboratories can ensure a reliable, safe, and efficient connection between fume hoods and ventilation ducts, minimizing risks to personnel and equipment.
