ANSI ESD STM3.1-2015 PDF

Full title and description

ANSI/ESD STM3.1-2015 — ESD Association Standard Test Method for the Protection of Electrostatic Discharge Susceptible Items: Ionization. This test method specifies procedures and measurement techniques to evaluate and select air ionization equipment and systems (ionizers), including methods for determining offset voltage (ion balance) and charge neutralization (discharge) time under specified conditions. The document explicitly excludes measurements of electromagnetic interference (EMI) and use with ordnance, flammables, explosive items, or electrically initiated explosive devices.

Abstract

Provides standardized laboratory and field test procedures to measure ionizer performance (offset voltage/ion balance and neutralization time) so users can compare, specify, and qualify air ionization devices for ESD control programs. The method defines test arrangements, environmental conditions, instrumentation, and reporting requirements necessary to produce repeatable, comparable results.

General information

• Status: Superseded (2015 edition; later revised — see Related standards).
• Publication date: November 19, 2015.
• Publisher: EOS/ESD Association, Inc. (commonly referenced as the ESD Association).
• ICS / categories: Electrostatics / ESD-related categories (commonly mapped to ICS codes used for electrostatics standards such as 17.220.99 and 29.020).
• Edition / version: 2015 edition (ANSI/ESD STM3.1-2015).
• Number of pages: 35 pages (2015 edition).

Scope

This test method establishes measurement techniques, apparatus arrangements, environmental and procedural requirements to determine ionizer offset voltage (ion balance) and charge neutralization time for ionizers used in ESD control environments. It is intended for specification, evaluation, comparison and selection of ionization equipment but does not address EMI performance or applications involving ordnance, flammables, explosives, or electrically initiated explosive devices. (Note: the STM3.1 family has been harmonized with IEC guidance in subsequent revisions; see Related standards.)

Key topics and requirements

• Definitions and terminology for ionization and ionizer performance metrics (offset voltage, ion balance, neutralization time).
• Test arrangements and measurement setups (probe types, distances, test specimen locations, environmental controls).
• Procedures for measuring offset voltage (ion balance) and discharge/neutralization time under specified charge and environmental conditions.
• Requirements for test instrumentation accuracy, calibration, and reporting of results to ensure comparability.
• Limitations and exclusions (EMI, explosive/flammable environments, electrically initiated explosive devices).

Typical use and users

Used by ESD engineers, test laboratories, QA/qualification teams, procurement/specification authors, and manufacturers of ionization equipment to evaluate, specify, and verify ionizer performance for ESD control programs in electronics assembly, manufacturing, and handling environments. Laboratories performing product qualification or vendor comparison commonly apply this method.

Related standards

STM3.1 sits within the ESD Association suite of ESD control test methods and is commonly used alongside related documents such as ANSI/ESD SP3.3 (periodic verification of ionizers), ANSI/ESD S20.20 (ESD program requirements), and material/packaging test methods (STM11.x series, S541). STM3.1 has also been harmonized with IEC work — later STM3.1 revisions reference or are technically aligned with IEC 61340-4-7. Note that a revised STM3.1 edition (STM3.1-2024) was published by the ESD Association; users should check whether the 2015 edition or the newer revision is the applicable document for their program.

Keywords

ionization, ionizer, offset voltage, ion balance, neutralization time, discharge time, ESD, electrostatic discharge, test method, ESD Association, ionizer qualification, ESD control.

FAQ

Q: What is this standard?

A: ANSI/ESD STM3.1-2015 is an ESD Association standard test method that defines procedures to measure ionizer performance (ion balance/offset voltage and charge neutralization time) for use in ESD control programs.

Q: What does it cover?

A: It covers laboratory and field measurement techniques, test arrangements, instrumentation and reporting for determining ionizer offset voltage (ion balance) and neutralization (discharge) time. It excludes EMI measurements and use with ordnance, flammables, explosive items, or electrically initiated explosive devices.

Q: Who typically uses it?

A: ESD/control engineers, test labs, quality and procurement teams, and ionizer manufacturers use the method to specify, compare and qualify ionization equipment for manufacturing and handling of electrostatic discharge sensitive items.

Q: Is it current or superseded?

A: The 2015 edition (ANSI/ESD STM3.1-2015) has been superseded by a later revision (STM3.1-2024). Users should confirm which edition is required by contract or company procedure; many organizations update to the latest edition to remain aligned with harmonized IEC guidance.

Q: Is it part of a series?

A: Yes — STM3.1 is part of the ESD Association's suite of ESD test methods and guidance documents (STM and S-series standards), and it is often referenced alongside STM11.x, SP3.3, S20.20, S541 and related IEC documents in the 61340 family.

Q: What are the key keywords?

A: Ionization, ionizer, offset voltage, ion balance, neutralization time, discharge time, ESD test method, ESD Association.