42530 - Desco - Datasheet.Live

TB-2000 February 2015 Page 1 of 4

Installation and

Maintenance of ESD Mats

Introduction

The purpose of an ESD worksurface is to aid in the prevention

of damage to ESD sensitive components and assemblies from

electrostatic discharge. An ESD worksurface provides protection in

the following two ways:

1. Providing an antistatic worksurface area that will limit static

electricity generation.

2. Removing the charge from a conductive object placed on the

worksurface.

A dissipative worksurface having a surface resistance of at least 1

x 106, but less than 1 x 109 ohms is recommended by worksurface

standard ANSI/ESD S4.1. Dissipative materials minimize the

generation of static charges, and will dissipate a charge slow

enough so that a spark will not occur. Dissipative materials are

usually the preferred choice for bench top worksurfaces.

Conductive materials are the quickest to remove a charge,

but they can also cause damage by discharging too rapidly.

Conductive materials are usually used as floor mats, which is

defined by ANSI/ESD S7.1 as less than 1 x 106 ohms.

General Grounding Guidelines

1. ANSI/ESD S20.20 requires that all conductors in an ESD

protected area, including personnel, must be grounded.

2. The ESD ground must be tied directly to and at the same

potential as the building or “green wire” equipment ground.

3. Per ANSI/ESD S20.20, the ESD control program can in no

way replace or supercede any requirements for personnel

safety. Ground fault circuit interrupters (GFCI) and other safety

protection should be considered wherever personnel might

come into contact with electrical sources.

4. All electrical outlets should be verified for proper wiring

configuration, resistance or impedance and GFCI function when

the mat is installed and periodically thereafter.

Common Point Grounds

A common point ground is defined by the grounding standard

ANSI/ESD S6.1, as:

1. A grounded device where two or more conductors are bonded.

2. A system or method for connecting two or more grounding

conductors to the same electrical potential.

Examples of common point grounds with ground cords are

illustrated below.

Figure 2. Other ground cords.

Figure 3. 09814 with screw allows ground cord to be bolted to mat

to keep cord from disconnecting.

Common point grounds are designed to provide ground for

worksurface mats, wrist straps, and other items.

NOTE: DO NOT DAISY CHAIN. Because of the high resistances

inherent to many types of protective surfaces, daisy chaining of

these materials can severely limit their ability to properly dissipate

and protect against static charges.

09817

09814

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Web Site: Desco.com

TECHNICAL BULLETIN TB-2000

Made in the

United States of America

Employee Owned

09835

09740

Figure 1. Typical common point grounds.

09837

09825

COMMON POINT GROUND

Per ANSI/ESD S6.1, Grounding section 4.1.1 “Every element to be

grounded at an ESD protected station shall be connected to the

same common point ground.”

ESD Handbook ESD TR20.20 section 5.1.3 Basic Grounding

Requirements “The first step in ensuring that everything in an

EPA is at the same electrical potential is to ground all conductive

components of the work area (worksurfaces, people, equipment,

etc.) to the same electrical ground point. This point is called the

common point ground. The next step in completing the ground

circuit is to connect the common point ground to the equipment

ground (third wire, green).”

WRONG!

RIGHT

Figure 4. ESD mats should never be grounded in series, that is

daisy chained.

TB-2000 Page 2 of 4

Grounding Methods

Method 1 (Grounding via ground cords)

1. Desco recommends using a common point ground cord when

grounding via ground cords. Most common point ground cords

will ground your ESD worksurface and provide banana jack

ground points for two wrist straps.

2. A common point ground should be installed at each workstation

and should be connected directly to a verified “green wire”

equipment ground. Only one groundable point should exist on a

worksurface.

Figure 5. Common point ground for each workstation.

3. Wrist straps should never be grounded through a worksurface,

as the added resistance of the worksurface material will

prevent the wrist strap from operating properly.

Figure 6. Proper grounding of wrist straps.

4. Per ANSI/ESD S1.1, a current limiting resistor in the wrist strap

ground cord is recommended. If other than a one megohm

resistor, special marking in red is required.

For additional information on grounding we recommend Desco

Technical Bulletin TB-2007.

Groundable Point Installation

1. Before installing a groundable point on your mat you must first

determine whether you will need a snap socket or stud, the

type of snap hardware and the location.

2. Desco has three types of 10mm (0.395") field installable mat

grounding snaps. The first type is a screw-on snap kit Desco

item number 09864 Universal Snap Kit.

A. Determine the position of the grounding snap (one only

per mat) and type of fastener you will be installing (socket

or stud). Take precautions not to cut your hand, and punch

a hole through the material with a small Phillips screwdriver

or awl.

B. Remove the release paper from the circular common point

ground label and affix it so that it aligns with the hole on the

material.

C. Select one of the screws as follows:

Material less than 0.100" thick - short screw

Material greater than 0.100" thick - long screw

D. Insert the screw through the top on the snap stud or socket,

the washer, the label and the material. Affix the assembly

with the conical nut supplied with the kit and tighten down

the screw using a Phillips screwdriver.

E. Remaining will be either a 10mm stud or socket, and either

a long or short screw to be discarded or saved for another

application.

ASSEMBLE

SCREW, STUD,

WASHER, LABEL

AND CONICAL NUT

AS SHOWN

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Web Site: Desco.com

WRONG! RIGHT!

Figure 8. Installing Universal Snap Kit on mat.

USE A PHILLIPS

SCREWDRIVER OR

AWL TO PUNCH

A HOLE IN THE

MATERIAL

Employee Owned

Figure 7. Three kinds of snaps.

3. The second type of mat grounding snap is the push and

clinch snap. This snap is designed for use with any type of

soft mat material: dissipative, conductive or multi-layered. It is

recommended for use with three-layered material, because it

provides excellent contact with the internal con ductive scrim

layer. It is recommended that before inserting this snap, the

mat be punctured with a sharp tool where the snap will be

placed. Take precautions not to cut your hand. Push and Clinch

snaps are available as a snap stud as item 09861 and as a snap

socket as item 09863.

A. Remove the release paper from the circular label and

affix it onto the mat material in the desired location.

B. Center the prongs on the snap assembly with the label.

Apply pressure to the snap until the prongs come through

the back of the mat, then clinch over prongs to secure snap

as shown in Figure 9.

TB-2000 Page 3 of 4

Figure 9. Installing push and clinch mat grounding snap.

4. The third type is the rivet style mat grounding snap. This type

of snap assembly is installed using a rivetting hand tool, item

09867. Male snap studs and rivets are available as item 09856

and female snap sockets and rivets are available as item

09857. Groundable point labels are not included with either the

item 09856 or 09857 snap kits.

Selection of Common Point and

Floor Mat Grounding Systems

1. Determine the type of common point grounding system you will

use: barrier strip, bus bar, grounding block, or common point

ground cord. Desco recommends the use of common point

ground cords or our 09740 dual bench mount.

2. If you determine that you will use ground cords, you must

now determine the type of ground cord you will use for your

workstation grounds. ANSI/ESD S6.1 recommends that a

non-resistor ground cord be used to ground worksurfaces and

floor mats. However, cord may have a 1 megohm resistor for

non ESD puropses. Selection of the ground cord is determined

by user needs and specifications.

4. The 09740 dual bench mount allows the grounding of

two operators at one common point. The 09740 mounts

easily under the front edge of a workstation. For

detailed information on this common point grounding

device ask for Technical Bulletin TB-2003.

Socket Stud

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Web Site: Desco.com

Employee Owned

3. The 09837 Multi Ground

Hub is designed for

use as either a multiple

grounding block or as a

common point ground.

The Multi Ground

Hub incorporates six

standard banana jacks,

and six terminations for

ring terminals (10-32

screw in threaded

holes). Note: Also

available as Desco item

19219 Ground Hub

Monitor

Figure 11. Mounting the 09837

to a table leg.

Figure 10. Installation using a rivetting hand tool.

1 Megohm

Resistor

Model #

09814

09813

09817

09818

09820

09821

09825

09826

09835

09836

09837

09740

09741

Designed

for Floor

Mat Use

Designed for

Worksurface

Use

Wire

Length

15'

10'

15'

10'

Banana

Jacks

Desco Ground Cord Item Numbers

Common

Ground

Point

Equipment

Ground

Worksurface Mat

Snap Ground

Floor Mat

Ground

Snap

Wrist Strap

Ground

Do Not Hook

A Second

Surface or

Device Here

Figure 12. 09740 dual bench mount.

TB-2000 Page 4 of 4

Figure 14. Hooking up ground cords.

4. If your installation includes a floor mat, you should duplicate

step 2 and attach the floor mat ground to the same point as the

worksurface ground wire.

5. Measure the resistance from the ground snap on the mat to

the common ground point. It should read 1 megohm ± 20

percent if you are using a ground cord with a resistor, and less

than 1 ohm if you are using a non-resistor ground cord.

6. Using a surface resistance tester per ESD TR53, test the

resistance to ground from the center of the mat surface.

Required equipment: a megohmmeter with 100 volt open test

circuit voltage and two five pound electrodes per ASTM-150.

Desco sells this as the Digital Surface Resistance Meter

Kit, item 19787. For more information on the 19787, ask for

Technical Bulletin TB-3062.

Limited Warranty, Warranty Exclusions, Limit of Liability

and RMA Request Instructions

See Desco’s Terms and Conditions -

http://desco.descoindustries.com/TermsAndConditions.aspx

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Web Site: Desco.com

Figure 13. Installing 09814 to mat using supplied hardware.

Mat Installation - General Information

1. For best results, allow the mats to lay flat for about four

hours at room temperature before installing. This will give the

material time to flatten out from being rolled for shipment.

2. Test grounds for proper resistance to ground. See Desco

Technical Bulletin TB-2007 for a complete discussion of

grounds.

3. Lay the mat in position and snap the ground cord to it. Bring

the other end of the ground cord to the common ground point

and attach it using the ring terminal. A suggested ground point

is the center screw of a standard AC electrical outlet. Testing is

recommended to ensure that the screw is properly grounded.

Tie the ground wire to the bench to keep it out of the way and

neat. You may cut and strip the ground wire to a shorter length

and attach it with the extra ring terminal included with each

Desco ground cord.

Figure 15. Adding the wriststrap.

BE SURE YOU TEST ALL GROUNDS AND THE WRIST STRAP

FREQUENTLY.

The following bulletins are available from Desco:

TB-2004 Operation of 19350 Wrist Strap Tester

TB-2005 Wrist Straps, Grounding, Testing, Maintenance

TB-2007 Safe Grounding of Static Controlled Workstations

Maintenance and Cleaning

For optimum performance, periodic cleaning is required following

manufacturer’s recommendations. Desco recommends Reztore™

Surface and Mat Cleaner for workstation mats and other surfaces

and Statguard® Floor Mat Cleaner for floor mats.

Note: Desco’s Reztore™ Surface and Statguard® Floor Mat

Cleaners contain no silicone or harsh solvents. Cleaners with

silicone leave an insulative residue on surfaces and solvents such

as 2-Butoxyethanol or Ethanolamine used in cleaners can dry out

the material; both can prevent conductive or dissipative mats from

functioning properly.

09825 / 09826

“GREEN WIRE”

UTILITY

GROUND

POINTS

RING

TERMINAL

CAN BE

ATTACHED

HERE

Employee Owned

7. If you are using a mat kit that includes the wrist strap, install

the wrist strap directly to the common point mat ground cord

banana jack. Again, test the resistance from the backplate of

the wrist strap to the common ground point. It should read 1

Megohm ± 20 percent.

6. The 09813 / 09814 mat ground cord may be either attached to

a mat by snapping onto a 10mm socket, or by bolting it to the

mat with the hardware supplied with the cord. When bolting

the 09814 to the mat use a 3/8" diameter hole punch to create

the hole for mounting. This will allow cord to sit flush on the

mat. Note: For both applications, remove screw from floor mat

ground before attaching to mat.