ESD workstations and work surfaces have one major objective–to ensure that all static-sensitive items are handled in an environment with the same electrical potential. Each provides a static-dissipative discharge path and uses an electrical path to ground to remove electrostatic charges.
The appropriate voltage susceptibility and minimum grounding and construction requirements for your operation are best determined by applying the guidance offered by the ESD Association and military standards.1 Use these standards to verify the proper operation of your ESD workstation or work surface:
ANSI EOS/ESD S4.1-1990 Worksurfaces–Resistive Characterization: Establishes test methods for measuring the electrical resistance of work-surface materials used at workstations for protection of ESD-susceptible items. It includes methods for evaluating and selecting materials, testing new work-surface installations, and testing previously installed work surfaces.
ANSI EOS/ESD S6.1-1991 Grounding–Recommended Practices: Recommends the parameters, procedures and types of materials needed to establish an ESD grounding system for the protection of electronic hardware from ESD damage. This system is used for personnel grounding devices, work surfaces, chairs, carts, floors and other related equipment.
MIL-STD 1686A ESD Control Program for Protection of Electrical and Electronic Parts, Assemblies and Equipment: Defines the basic elements of an ESD program and requirements for their implementation.
MIL-W-87893A Workstation, ESD Control: Contains test methods and specifications for physical and electrical properties of ESD-control workstations, common-point grounds and wrist straps.
These documents are not full standards but may provide helpful information:
ESD DS12.1-1995 Seating–Resistive Characterization: Provides test methods for measuring the electrical resistance of seating used to control ESD. The test methods can be used for qualification testing and evaluating and monitoring seating after installation or application. It covers all types of seating, including chairs and stools.
ESD ADV53.1-1995 ESD Protective Workstations: An advisory document that outlines the minimum requirements for a basic ESD-protective workstation used in ESD-sensitive areas. It provides a test method for evaluating and monitoring workstations. It defines workstations as having a support structure, a static-dissipative work surface, a means of grounding personnel and, if appropriate, attached shelving or drawers.
For information on electrical needs, ergonomic issues, seating, overhead equipment, design flexibility and lighting, consult the manufacturers. They can provide the choices that allow the best and most flexible design for your needs.
Reference
1. Standards Catalog and Price List, ESD Association, November 1995, (315) 339-6937.
Workstation/Work-Surface Products
Silver-Based Laminate Used As
Backing Sheet or Liner
STATICPLAS® is a silver-based, tabletop laminate that provides a conductive surface for use in clean rooms. The material has a surface resistivity of 108 W /sq and can be used as a backing sheet or cabinet liner. Version 42 is 0.042″ thick and is available in 10 colors and in sizes ranging from 36″ x 96″ to 60″ x 144″. Version 30 is 0.030″ thick and is supplied in eight solid colors and five sizes. The material resists acids, alkalines and alcohol. Antistatic Industries, (201) 489-4400.
Modular Systems Available
As Single- or Double-Sided
A line of ESD modular workstations features single- or double-sided versions. Tabletops, vertical panels, slide-rail assemblies, light fixtures, chairs and footrests are available in a variety of sizes and colors. The universal leg assembly is made from 12-gauge steel and the joints are welded. The white laminated tabletop is static-dissipative with a surface resistivity from 106 W /sq to 109 W /sq. The ground lug is made from stainless steel and uses a 1/4″ terminal. Benchmark Engineering, (310) 693-5425.
Seating Height Is
Pneumatically Controlled
The Microtech™ line of seating incorporates pneumatic controls for adjusting seat height. An all-metal frame and component construction drain away static charges. Either conductive or static-dissipative upholstery can be used on the backrest, seat and armrests. The rate of charge decay of the fabrics ranges from 0.63 s to 0.01 s. Top surface resistivity ranges from 2.6 x 102 W /sq to 5.0 x 105 W /sq. BioFit Engineered Seating, (800) 597-0246.
Solid-Fiber Shelf Liners
Are Resistant to Solder
PRO-MAT™ is a solid-fiber, 100%-recyclable material resistant to solder. The shelf-liner material is applied to a variety of surfaces, including wood or steel shelving and circuit-board carts. It provides surface resistivity of 107 W /sq to 1010 W /sq and has a buried shielding layer measuring 104 W /sq. The liner contains a 3/8″ grounding snap. Sizes range from 11 3/4″ x 59 1/2″ x 0.60″ to 23 1/2″ x 59 1/2″ x 0.60″. Brick Container, (310) 903-9392.
Retrofitting and Customizing
Offered for Workstations
Customizing and retrofitting services include installing hydraulic or mechanical screw-gear systems to convert a stationary, fixed-height workstation to an adjustable version. This service can also make existing workstations clean-room safe. Customized workbenches can be equipped with electric conduits, air connections, custom work surfaces, shelving, risers, overhead trolley systems, lights and drawers. Custom Products & Services, (612) 452-0113.
Workstation Has
Insulated Receptacles
The Sturdilite ESD Workstation System includes insulated receptacles that prevent ground loops. Each drawer is grounded to the work-surface ground terminus. All work surfaces and shelves are supplied with grounding kits containing two ground termini. The work surface laminate provides a resistance of 1 x 106 W to 1 x 109 W . Kewaunee Scientific, (512) 398-5292.
ESD-Grade Production Bench
Supports 4,000 Pounds
The Lissner Production Bench features 1.25″-thick tops, sealed bottoms and 0.042″-thick Formica laminates on the top and four sides. Dual banana jacks are provided for left- and right-handed personnel. Steel tubing legs coupled with 2″ x 1.5″ steel tubing stringers support up to 4,000 lb. Options include footrests, UL-rated power strips, adjustable shelving, lighting, plastic or metal drawers, and casters. Lissner, (800) 735-4500.
Three-Layer Mat Has
Conductive, Dissipative Layers
The Hi Performance Mat provides protection for static-sensitive components. The three-layer design has a conductive center and a static-dissipative top layer with a maximum top-to-top resistance of 107 W @100 V. Volume resistivity is <1010 W · cm. Matting is available in pre-cut sizes with a common-point ground cord and connection, or by the linear foot. NRD, (800) 525-8076.
Mat Exceeds NEMA Standard
For Wear Resistance
Micastat Dissipative Laminate #15004 provides a permanent ESD-control work surface. It is installed permanently on a workbench, resists hot solder and most solvents, and exceeds NEMA standards for wear resistance. The laminate is constructed in multiple layers with a conductive layer for charge dissipation. The top has a surface resistivity of 2 x 109 W /sq. The material meets the guidelines of work surfaces per EOS/ESD S-4.1. Plastic Systems, (508) 485-7390
Workstation Height Adjusts
From 31″ to 42″
The ERGONIZER Workstation adjusts to operator needs. Table heights range from 31″ to 42″. The work-surface is 36″ x 60″ and includes a 180° rolled front edge. The tabletop supports a 500-lb distributed static load and is available with an ESD laminate. Accessories include lighting, storage and electrical outlets. Production Industries, (909) 272-0555.
Workstation Series
Offered in Four Designs
Each of the four workstation configurations in the StaticGard® Series features laminated static-dissipative tops with compatible ESD-protective bench legs, cabinets and work-surface shelves. A central personnel and equipment grounding point is included. Point-to-point resistance and point-to-common point grounding resistance are 106 W to 1010 W . The series includes configurations for maintenance, technical assembly, inspection and packaging applications. Stanley Storage Systems, (800) 523-9462.
Modular Workstation Offers
Fixed or Adjustable Height
ErgoStat™ is a modular workstation capable of handling a dynamic load of 500 lb. It can be equipped with a range of standard components and accessories, including shelves, bin rails, tool arms and lighting. Some models have electrically or hydraulically adjustable surfaces; others feature a fixed height. The work-surface height adjusts from 26.5″ to 42.5″. Fixed bases are either 27.375″ or 34.375″ high. The workstation frame and components are static-dissipative. Symbiote, (616) 396-0377.
Workstation Provides
Grounded Chairs, Lighting
The Workbench Systems line of ESD-controlled workstations includes hard work-surface laminates, lighting, wrist straps, constant ground-fault monitors, dissipative pads and grounded chairs. The company also offers a planning and design service to assist customers in selecting ESD workstations. Teclab/Kalamazoo Technical Furniture, (800) 832-5227.
Hard Laminate Ready-Made
For Workbenches
The 3M 8300 Hard Laminate is ready-made for installation on workbenches requiring static protection and durability. The laminate can be shaped to a 1/2″ radius without cracking. Surface-to-ground resistance is 7 x 106 W , surface-to-surface resistance is 5 x 107 W , and surface resistivity is 4 x 108 W /sq. The colors are beige, gray, blue and white. Tabletop sizes include 3’ x 12’, 4’ x 8’ and 5’ x 12’. 3M, Electrical Specialties Division, (512) 984-2146.
Three-Layer Mat
Has RTG of 107 W
The Dissimat Serial 51 is a three-layer PVC mat that provides a resistance to ground and resistance top-to-top of 107 W , per ESD S-4.1. The 0.125″-thick mat has a surface resistivity of 108 W /sq and a volume resistivity of 108 W · cm. It is available in light blue. Bystat International, (800) 361-6777.
Workbenches Offer
Height-Adjustable Surfaces
The 900 Pro Series now offers the Model 950 Pro with hand-cranked adjustable surfaces and the Model 960 Pro with motorized, push-button adjustable surfaces. The stand-alone workbenches have a variety of options, including ESD worksurfaces, several sizes of frame-mounted drawers and cabinets, wire shelves, overhead light fixtures, full-length electrical raceways, frame-mounted footrests and the company’s new rear-mounted Multi-Task System upper structure. The work surface height adjusts from 26″ to 38″. The benches support 500 lb of evenly distributed static loads. IAC Industries, (714) 990-8997.
Copyright 1996 Nelson Publishing Inc.
January 1996