Gentek 3940220, 3940200, 3950320, 3950202, 3940421 Humidity and Static Electricity Requirements

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Chapter 2: Prerequisites

Humidity and Static Electricity

Requirements

Electrostatics can be troublesome in a balance enclosure. It is important to understand and, to the extent possible, control static charges. An electrostatic charged vessel, sample or enclosure can apply forces and lead to errors in weighing. The repulsion or attraction can be detected with micro, semi micro and analytical balances. Static charges can also lead to particulates being attracted to surfaces within the balance enclosure. Containment of harmful powders, prevention of cross-contamination and clean up are enhanced when static attraction of powders is minimized. The construction of the XPert Filtered Balance System and XPert Filtered Balance Station avoid the use of plastics, which are highly insulative. The advantages to the glass and epoxy-coated metal construction are twofold:

1.The enclosure does not contribute high electrostatic forces affecting the precision of the balance.

2.The attraction and ultimate accumulation of powders, (hazardous or nuisance), are minimized on the inside of the enclosure.

To correct or ensure against electrostatic issues, the following additional measures may be prescribed to improve weighing operations.

•Maintain a humidity level between 45 and 60%. The ability to sustain this humidity range can be challenging depending upon the regional climate and HVAC system.

•Ionizers in various forms (guns, bars and blowers) are effective ways to flood an area with ions and essentially “neutralize” electrostatic electricity.

Background on Electrostatics or

Static Electricity

Electrostatic charges on a surface such as the wall of a balance enclosure are not created by moving air. Gases do not cause the charge. Impurities within the air impinging upon surfaces dictate the polarity and magnitude of the charge. The process, triboelectrification, occurs when the dust particles contact the surface, creating friction and electrons move across the interface.

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Contents User’s Manual USA Warranty Able Ontents PrerequisitesMaintaining Your Filtered Enclosure Chapter Introduction Introduction About This Manual Typographical Conventions Chapter Prerequisites Temperature Variation Requirements Support, Vibration and Movement RequirementsHumidity and Static Electricity Requirements Background on Electrostatics or Static ElectricityLocation and Air Current Requirements Exhaust and Blower RequirementsSurface Resistivity Table XPert Station Electrical Requirements Space RequirementsChapter Getting Started Lift by the front air foilUnpacking the Enclosure Do not move the enclosure by tilting it onto a hand truckWork Surface Specifications Work Surface and Hepa Filtered Enclosure InstallationFiltered Enclosure Installation XPert Station Getting Started Getting Started Installation of Hepa Filters Accessory Odor Control Carbon Carbon Filters Accessory for Odor Control onlyHepa Filters Filter Type Appropriate Use 115V ModelsGetting Started Set the Face Velocity with the Speed Control Adjustment Validating the Vented EnclosureSealing the Filtered Enclosure to the Work Surface Chapter High Performance Features and Safety Precautions High Performance FeaturesHigh Performance Features and Safety 1510 Hepa Filtered Enclosure Airflow Diagram High Performance Features and Safety High Performance Features and Safety High Performance Features and Safety High Performance Features and Safety Safety Precautions High Performance Features and Safety High Performance Features and Safety High Performance Features and Safety Routine Daily Work Procedures PlanningStart-up Loading Materials and EquipmentWork Techniques Final PurgingSuitable Applications Hepa Filter Applications Suitability and GuidelinesShutdown Odor Control Carbon Filter Applications sold as an accessory Definition of Terms Appropriate Chemicals for Odor Control Carbon Filters Chemical Carcinogen Use with Odor Control Carbon Filters Prohibited Acid UseBalance Station, which uses a remote blower Chapter Maintaining Your Filtered Enclosure Routine Maintenance Schedule WeeklyMonthly or more often as required Determination of when to Replace Hepa Filters DecontaminationAnnually Maintaining Your Filtered Enclosure Hepa Filter Leak Test PurposeMineral oil Catalog #1491400 Acceptance Labconco Airflow Monitor / Airflow Switch Operation Calibrate and Operate the Airflow MonitorsGuardian Airflow Monitor LED Monitor Enclosure Operating In-Flow Alarm Condition Set Point Speed CalibrationGuardian Airflow Monitor LED with Airflow Switch Guardian Digital 1000 Airflow MonitorOperation Digital 1000 CalibrationFactory Settings Guardian Digital 1000 Airflow Monitor Maintaining Your Filtered Enclosure Odor Control Carbon Filter Replacement Procedure See Calculating Odor Control Carbon Filter Life Steps for Calculating PPM and Filter LifeInitial Certification Re-CertificationFormaldehyde only Ammonia onlyFluorescent Light Replacement Motorized Impeller ReplacementMotorized Impeller Replacement Speed Control Replacement Chapter Accessorizing Modifying Your Filtered Enclosure Work SurfacesAdd appropriate Front Panel with cutout to mount Digital Airflow MonitorExhaust Transition Kits for Ducting to Outside Part Description Remote BlowersAccessory Filters Hepa Filter Exhaust DampersHepa Filter Bag-In/Bag-Out Bag Odor Control Carbon FilterStorage Cabinets Utility Shelf KitAccessorizing and Modifying your Filtered Enclosure Chapter Troubleshooting Servicer Operating LOG Problem Cause Corrective ActionTroubleshooting Problem Cause Corrective Action Service Operating Record Log Date CommentsAppendix a Filtered Enclosure Components Replacement Parts Qty Part Number Description Qty Part Number Description Long Use for XPert System and XPert Station Use for XPert System, XPert Station, Digital Monitor and Bag Appendix B Dimensions Exhaust Options Figure B-1 XPert Filtered Balance System Figure B-2 XPert Filtered Balance Station Appendix B Dimensions and Exhaust Options Appendix C Filtered Enclosure Specifications Environmental ConditionsAppendix C Filtered Enclosure Specifications Appendix C Filtered Enclosure Specifications Appendix C Filtered Enclosure Specifications Appendix C Filtered Enclosure Specifications Appendix C Filtered Enclosure Specifications Ppendix Uick Hart Iltered Nclosures Model SizeNon-mandatory recommendations from Prudent Practices Appendix E References Nfpa 30 2000 Flammable and Combustible Liquids Code General References Laboratory Safety, Principles and Practices, American Page USA