ISO/ASTM DIS 52961:2025(en)

ISO/TC 261-ASTM F42

Secretariat: DIN

Date: 2025-11-05

Additive manufacturing of polymers — Environment, health and safety — General principles for use of polymers with material extrusion

Fabrication additive de polymères — Environnement, santé et sécurité — Principes généraux pour l’utilisation des polymères avec extrusion de matériau

© ISO/ASTM International 2025

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of the requester. In the United States, such requests should be sent to ASTM International.

ISO copyright office ASTM International

CP 401 • Ch. de Blandonnet 8 100 Barr Harbor Drive, PO Box C700

CH-1214 Vernier, Geneva West Conshohocken, PA 19428‑2959, USA

Phone: +41 22 749 01 11 Phone: +610 832 9634

Fax: +610 832 9635

Email: copyright@iso.org Email: khooper@astm.org

Website: www.iso.org Website: www.astm.org

Contents

Foreword v

Introduction vi

1 Scope 1

2 Normative references 1

3 Terms and definitions 1

4 Abbreviations 1

5 Methodology 2

5.1 General 2

5.2 Chemical hazard methodology 4

6 Source data 5

6.1 General 5

6.2 Input products and by-products 5

6.2.1 Safety data sheet 5

6.2.2 Product technical datasheet 5

6.3 Process 5

6.3.1 General 5

6.3.2 Means of storage and implementation 5

6.4 Feedback from experience 6

6.4.1 Incident reports 6

6.4.2 Technical and normative watch 6

6.4.3 Measurement reports and analyses 6

7 Risk assessment 7

7.1 Identification of hazards 7

7.2 Documentation on hazards 7

7.2.1 General 7

7.2.2 Identification of hazards related to inputs 7

7.2.3 Hazards related to substances generated during material extrusion process 13

7.2.4 Hazards related to fire and explosion 13

7.3 Identification of exposing situations 13

7.4 Characterization and risk rating 17

7.4.1 General 17

7.4.2 Rating of risks related to contamination, inhalation or skin contact 17

7.4.3 Rating the risks related to explosion 18

8 Prevention and protective measures 19

8.1 General 19

8.2 Workplaces 19

8.2.1 Floors and walls 19

8.2.2 Air flow rate 20

8.2.3 Fire 20

8.2.4 Electric 21

8.2.5 Material storage 21

8.2.6 Best practices for workplaces for personnel 21

8.3 Process 22

8.4 Organization 22

8.4.1 General 22

8.4.2 Training of personnel 22

8.4.3 Information for personnel 23

8.4.4 Limitation of exposed personnel 23

8.4.5 Reduction of exposure 23

8.4.6 Personal protective equipment 24

8.5 Waste management 25

8.5.1 General 25

8.5.2 Contaminated filters 25

8.5.3 General dry waste 26

Annex A (normative) Safety data sheet 27

Annex B (normative) Definition of limit values 29

B.1 General 29

B.2 Relevant agencies worldwide 29

Annex C (normative) Hazards related to fire and explosion 30

C.1 General 30

C.2 Material combustibility 30

C.3 Ignition source control 30

Annex D (informative) Overview of OEL for substances 31

Bibliography 34

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

The committee responsible for this document is ISO/TC 261, Additive manufacturing, in cooperation with ASTM Committee F42, Additive manufacturing technologies, on the basis of a partnership agreement between ISO and ASTM International with the aim to create a common set of ISO/ASTM standards on additive manufacturing, in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 438, Additive manufacturing, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

The use of additive manufacturing (AM) processes with polymer materials entails a number of hazards. It is therefore important, as a first step, to implement a high level of protection during manufacturing and installation of the additive manufacturing machine or system.

In addition, the users of additive manufacturing plants have the duty to reduce the risks for the operators remaining after installation so that they fulfil the nationally or regionally pertinent regulations for health and safety at work. The latter are very different worldwide and the requirements of a standard cannot fully reflect them. For users of additive manufacturing plants, the guidelines and requirements of this document are, therefore, particularly relevant with regard to aspects not sufficiently covered by pertinent national or regional regulations for safety and health at work.

While this document outlines general principles and best practices to mitigate the hazards associated with polymeric additive manufacturing with material extrusion, these best practices intend to be generic and provide the users with the means to fulfil any local laws and regulations.

Additive manufacturing of polymers — Environment, health and safety — General principles for use of polymers with material extrusion

This document provides guidance and requirements for risk assessment and implementation of prevention and protection measures relating to material extrusion-based additive manufacturing with polymer materials.

The risks covered by this document concern all sub-processes composing the manufacturing process, including the management of waste.

This document does not specify requirements for the design of machinery and equipment used for additive manufacturing.

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 16321‑1, Eye and face protection for occupational use — Part 1: General requirements

ISO 16321‑3, Eye and face protection for occupational use — Part 3: Additional requirements for mesh protectors

ISO/ASTM 52900, Additive manufacturing — General principles — Fundamentals and vocabulary

IEC 60079‑10‑1, Explosive atmospheres — Part 10-1: Classification of areas — Explosive gas atmospheres

IEC 60079‑10‑2, Explosive atmospheres — Part 10-2: classification of areas — Combustible dust atmospheres

ANSI Z87.1, Practice for Occupational and Educational Eye and Face Protection

For the purposes of this document, the terms and definitions given in ISO/ASTM 52900 apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/

The abbreviations and acronyms used in this document are listed in Table 1.

Table 1 — Abbreviations and acronyms

The method described in this document allows the user to assess the EHS risks considering the following:

— polymer materials used;

— AM process;

— AM system installation conditions;

— applicable good practices;

— feedback from experience.

The methodology is based on a characterization of physical hazards (e.g. fire and explosion), hazards to the health of the operator or the potentially exposed third parties and to the environment. The overall approach to risk assessment and implementation of prevention measures is illustrated in Figure 1 and detailed in Table 2.

^a The top row of the flowchart represents each step of the methodology in sequential order, the source data being the first step that feeds to the risk assessment itself, all the way through the supervision as the last step (see Table 2).

Figure 1 — Overall approach to risk assessment and implementation of prevention measures

Table 2 — Content of the steps toward the evaluation and prevention of risks

The steps for assessing and controlling the risk of exposure to hazardous chemical agents are described in Figure 2:

Figure 2 — Main steps of a chemical risks prevention process

Applicable local regulations should be considered (see Directive 89/391/EEC in Europe and OSHA in USA).

See information given in Annex A.

The product technical datasheet should also contain information about polymer materials (additives, mechanical properties).

Technical specification of polymer materials should be provided in accordance with ISO/ASTM 52903-1:2020.

The instructions for proper installation, use and maintenance of the AM equipment and post processing equipment shall be followed. The user should ensure that the combination of feedstock and AM equipment and post processing equipment has been taken into account. The user shall perform a specific risk assessment, preferably with the support of the AM equipment and post processing equipment manufacturer and of the supplier of the feedstock(s).

For the regular use of polymer materials, national regulations and organisational policies related to hazardous substances should be observed. This would include registering of the material in the organization and risk assessments for the individual processes performed with the material based on information from the safety data sheets. This would provide hierarchical control for the following, as a minimum:

— material identification;

— storage location;

— storage requirements (legal aspects, safety aspects and material quality aspects);

— manual handling requirements;

— maximum volume/s of material for each process;

— use of ancillary equipment (wet separators, sieving units, etc.),

— housekeeping requirements;

— PPE requirements.

When an incident occurs for an operator of a facility, the company should provide a report analysing the causes of the incident, its effects and consequences on people and the environment. Information useful for in the incident report includes:

— description of the process and its equipment: implementation, products involved, operating conditions in normal operation, procedures, rules, control operations, maintenance, cleaning, etc.;

— safety measures (prevention, protection), procedures, qualifications, training;

— circumstances, context and chronology of the incident:

— operating context before and during the incident, product condition, identification of deviations from normal, testimonials, latest interventions (maintenance, control, inspections, interviews, work, other incidents...);

— chronology of events and incident management (interveners present, actions carried out, date/time, etc.);

— miscellaneous findings;

— characterization of the consequences:

— experimental characterization to remove doubts (measurement, incident reproduction, product characterization);

— characterization by modelling (e.g. fire in an AM workplace);

— recommendations: prevention, detection, protection, management of activities.

Technical and/or normative documents should be available, reviewed and the AM process updated as needed as soon as practicable after publication.

All emission measurements, either on receipt of the equipment or in normal operation, as well as the history of exposure measurements are useful feedback for risk assessment or re-assessment.

If the risk assessment shows that there is at least one exposure situation subject to a regulatory OEL, exposure levels shall be controlled in accordance with the regulations.

NOTE Currently, there are no known common cases in the field of AM with polymer materials requiring the intervention of an accredited body, but this cannot be excluded.

All hazardous chemicals and materials shall be identified. The prevention approach consists in systematically identifying the presence of such products and any working situation in which operators and other personnel could be exposed.

For AM workspaces and feedstock storage locations the use of chemical safety cards (CSC) is strongly recommended, and depending on local regulations, mandatory. Chemical safety cards provide the essential health and safety information of chemicals in a clear and concise manner. This includes information on hazards, required PPE and actions to be taken in the event of an accident or spill.

Chemical safety cards are available for pure substances only in the database mentioned in the note below. For mixtures, it is recommended that the employer composes a similar document based on the information provided in the safety data sheet (SDS) and structured in a similar way as a chemical safety card.

NOTE An extensive database of ready to use cards has been composed in the International Chemical Safety Cards (ICSC) project. This project is a collaboration between International Labour Organization (ILO) and the World Health Organization (WHO), with the cooperation of the European Commission. For more information see the following references:

https://www.ilo.org/dyn/icsc/showcard.home

https://www.who.int/publications/m/item/international-chemical-safety-cards-leaflet

https://www.cdc.gov/niosh/ipcs/default.html

General

The following requirements shall be satisfied, in order to identify the hazards related to polymer materials:

— consider the regulatory requirements that are relevant to the production and use site;

— identify the hazards related to each polymer material and by polymer family.

A guidance for understanding safety data sheets (SDSs) is given in Annex A.

Users should regularly check for the latest available updates of the SDS.

Identification of hazardous products

The classification information included in the safety data sheets sent by the polymer material supplier shall be taken into account. The safety data sheets shall be written in the language of the recipient country and accompany each product.

NOTE 1 In European countries, classification information is available in the classification, labelling and packaging regulation. For the other countries, it is suitable to refer to the national regulations or by default to the GHS regulation.

EXAMPLE Within the European Union, the CLP regulation gives the classification applicable to chemicals. They are classified into the following 3 families:

— substances (unitary chemical elements);

— mixtures (in the form of raw materials);

— articles (semi-finished products and finished products: bars, sheets, manufactured products, etc.).

— For mixtures, only in lack of specific data, the hazard shall be rated as the sum of the hazards of the substances, using the classification rules.

NOTE 2 Classification, labelling and packaging regulation of substances that are accessible and up to date on the website of ECHA make it possible to check whether Section 2 of the manufacturer's safety data sheet conforms. see the following: https://echa.europa.eu/fr/information-on-chemicals/cl-inventory-database

NOTE 3 Two sources exist for establishing the classification:

— EU member countries; this classification is said to be “harmonized”;

— manufacturers who generally come together into consortiums; this classification is said to be “joint submission”;

— REACH files have increased the numbers coming under this second classification.

NOTE 4 The GHS system of classification and labelling of chemicals is an international initiative under the guidance of UNECE. Parallel to GHS UNECE is also involved in the composition of guidelines concerning the safe transport of chemicals.

NOTE 5 While UNECE does not compose legislation, it is the intention to translate the suggested guidelines by UNECE into the local regulatory and legal framework of the governments involved. A list of participating countries and the status of the implementation in those countries can be found on the UNECE website. This includes links to the local governmental bodies and ratified texts.

https://www.unece.org/trans/danger/publi/ghs/implementation_e.html

NOTE 6 While in this document the term GHS is used freely understanding that the GHS guidelines are, or are to be, implemented worldwide, it is up to the reader to check the status of the local implementation.

Hazards related to the nature of products

Hazards are identified in Section 2 of the safety data sheet. The user shall take this into account.

The chemical risk depends on the hazard (see Table 4) and on the exposure. The exposure to chemical substances can occur mainly via three modes of penetration which are inhalation, skin contact, and ingestion.

Generally, the main routes for occupational exposure to polymer materials are inhalation (especially in dust form) as well as skin contact (for dust as well as for wires).

NOTE 1 OELs for dermal exposure are lacking and it is the responsibility of the user to decide on skin contamination criteria. Resources exist such as:

— NIOSH skin notations: https://www.cdc.gov/niosh/topics/skin/skin-notation_profiles.html;

— ACGIH provides skin and sens notations if applicable for polymers.

NOTE 2 For Europe, some information can be found in REACH and ECHA.

Mixtures shall in general be considered as substances. Only in lack of sufficient data for a mixture, for each polymer material of a mixture, an exposure assessment shall be conducted in order to establish a reference for the chemical risk related to exposure by inhalation.

NOTE 3 These data are indicated in Section 8 of the safety data sheet (See Annex A).

The relevant national regulations take precedence over any other reference. However, when there is no OEL in the applicable regulations, or when a significant difference exists related to more recent limit values, it is recommended to choose a reference that is more stringent than the applicable regulations. For all particles or dust not having any specific effect, the OEL is as follows:

—  4 mg/m³ for the total fraction;

— 5 mg/m³ for the breathable, respirable fraction or alveolar fraction.

A substance that is not classified in the classification, labelling and packaging regulation and that has an occupational exposure limit value identical to one of those references is not a substance with a specific chemical risk. Those references are therefore not indicators or drivers of the toxicity of an mixture.

NOTE 4 The “breathable fraction”, “alveolar fraction” or “respirable fraction” is the effective inhaled fraction that reaches the pulmonary alveoli, where the majority of it can penetrate into the person's system.

NOTE 5 There is an European database, GESTIS, which gives the OEL values for various countries available at:

https://www.dguv.de/ifa/gestis/gestis-internationale-grenzwerte-fuer-chemische-substanzen-limit-values-for-chemical-agents/index-2.jsp.

The European regulations are being drafted and certain new stringent occupational exposure limit values can be set.

Hazards related to particle size distribution

The particle size distribution is an important parameter to consider in prevention. A high concentration of fine particles generates health risks due to the physical nature of the particles (see Table 3). In the case of MEX processes with thermoplastic materials, the hazards related to particle size distribution are typically emissions from the process.

Table 3 — Effects of particles on health depending on particle size distribution

NOTE See EN 481 for details of the respective definition of size fractions.

Hazards identified per substance

A non-exhaustive list of OELs identified according to the substances is given in Annex D.

Hazards identified per family of polymers

The hazards identified per family of polymers are listed in Table 4.

Hazards identified per solvents used for cleaning operations

The hazards identified per solvents used for cleaning operations are listed in Table 5.

Table 4 — Hazards per polymers

Table 5 — Solvents used for cleaning operations

Under the effect of temperature, plastics degrade superficially, forming Volatile Organic Compounds (VOCs), some of which can cause irritation of the respiratory tract, or particles. ABS, for example, releases styrene and formaldehyde, which can have reprotoxic or carcinogenic effects.

The pollutants emitted during the process heating of polymeric materials can be determined with the help of:

— safety data sheets

— databases such as https://www.inrs.fr/publications/bdd/plastiques.html

Most degradation products are flammable. If they are present in sufficient concentration (in the absence of ventilation), they are likely to catch fire.

The use of any type of polymer powder can incur a fire or explosion hazard. The user shall be aware about the dust combustibility. If this information about the dust combustibility is not provided by the polymer material supplier, see Annex C for guidance. An additional dust explosion hazard is incurred when flammable material in powder form is suspended in the air, generating a dust cloud.

When using such flammable materials all ignition sources in the vicinity shall be avoided. These ignition sources include, but are not limited to, static discharge or static electricity, hot surfaces, open flames and live circuitry. It is the users' responsibility to apply the safety precautions as described in the system manufacturers manuals. Furthermore, sufficient measures shall be taken to limit static discharge, including the use of grounded antistatic equipment, antistatic work surfaces and floors and antistatic garments and grounding of personnel.

To perform the risk assessment, each step of the process shall be defined including the exposure in routine situations (production, cleaning, etc.) and during occasional activities (maintenance, accident, etc.). See Table 6.

Table 6 — Guidance list for the identification of exposing situations

The job description for operators working in the additive manufacturing area, and possibly on the parts produced by AM shall take into account the specific risks listed in 6.2. For the risk rating, all significant applicable risks shall be considered.

WARNING — The highrisk category should be evaluated by the operating company through a very detailed risk analysis.

For the risk rating, the hazard severity shall be classified in 3 levels according to Table 7.

Table 7 — Hazards for the operator depending on the level of severity

Exposure to CMR substances always leads to high level of severity. Low level of severity is only applicable for completely closed processes where no exposure to hazardous substances under normal working conditions occur.

For the risk rating, the exposure frequency shall be classified in 3 levels: high, medium and low levels. Example for an exposure frequencies characterization is shown in Table 8, for a manufacturing process conducted many times a day.

Table 8 — Characterization of the exposure frequencies

The level of risk is the product of severity by the exposure frequency. Based on appropriated and established criteria for the obtained product values, the risk shall be classified in 3 levels: high, medium and low levels. Example for a levels of risk characterization is shown in Table 9.

Table 9 — Level of risk as a function of frequency by severity

The prevention and protection measures to be implemented depend on the rating (see Table 10).

Table 10 — Preventive and/or protective measures according to the level of risk

NOTE The code of practice on Workplace Safety and Health Risk Management, 6.4.7 Action for risk levels (see Table 8) gives guidance. See the following website: https://www.tal.sg/wshc

It should be appropriate to use a rating by 3 levels of risk (1, 2, and 3).

The user should be aware that a feedstock which is not combustible can produce combustible particles and gases (e.g hydrogen) during the process. The user should recognize the electrostatic discharge contribution to fire and explosion risks.

As a part of the risk analysis, the explosion hazard shall be carried out. Zones for potentially explosive atmospheres shall be defined in accordance with IEC 60079‑10‑1 and IEC 60079‑10‑2. See Table 11.

Table 11 — Simplified definitions of Zones resulting from the application of
IEC 60079‑10‑1 and IEC 60079‑10‑2

The characteristics for zones are the following:

— Zone 0: A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist is present continuously or for long periods or frequently.

— Zone 1: A place in which an explosive atmosphere consisting of a mixture with air or flammable substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally.

— Zone 2: A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only.

— Zone 20: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently.

— Zone 21: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally.

— Zone 22: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only.

The assessment of residual risks is carried out by the user of the system through the application of the criteria of severity and frequency of the hazardous situation according to 7.3. Residual risks are those remaining after protective measures have been implemented.

NOTE The protective measures implemented by the responsible manufacturer/supplier of the AM system to achieve this objective are applied in the following sequence according to ISO 12100:2010, 6.1:

— inherently safe design measures to eliminate hazards or reduce the associated risks by a suitable choice of design features of the machine itself and/or interaction between the exposed persons and the machine. They mainly affect the process (see Figure 1).

— appropriately selected safeguarding and/or complementary protective measures taking into account the intended use and the reasonably foreseeable misuse to reduce risk when it is not practicable to eliminate a hazard, or reduce its associated risk sufficiently, using inherently safe design measures

Where risks remain despite inherently safe design measures, safeguarding and the adoption of complementary protective measures, the responsible manufacturer/supplier identifies the residual risks in the information for use (instruction manual, warnings, etc.). Other preventive measures shall be taken into account by suppliers of by-products through the obligation of substitution of hazardous products.

If required by the assessment of the residual risks the user of the system shall apply additional preventive measures. They can be technical (concerning e.g. process, input products and by-products, working rooms), organizational (e.g. adequate training) and/or personal (e.g. the wearing of personal protective equipment).

These additional protection measures are implemented by the user taking into account the information for use including in particular:

— the information provided by the manufacturer of the AM system through the instruction manual defining the limits of use in the different phases of life of the AM system;

— the safety data sheets (SDS) of the products implemented.

The implementation of the additional protection and/or prevention measures and the information required by the operator shall take into account the work environment and the results of the assessment of the residual risks established for all the operating phases of the AM system.

Protection and prevention measures are integrated according to the results of the risk assessment complying with Clause 7.

Sticky floor mats shall be provided for dust collecting at the access points to the production area in order to prevent powder from spreading.

The AM workplace shall be considered as place with specific EHS control requirements. Controls shall be in place to keep powder used in the AM system from escaping the room. The wall coating should be such that it does not retain the powder and is easy to clean.

NOTE Coating can be e.g. polyurethane type.

In case of combustible powders and with the risk of fire/explosion in the free state, the floor shall be static dissipative. In addition, and depending of the risk analysis, the walls should be also static dissipative.

The extracted air flow rate and the compensation air flow rate shall be defined to reduce the specific particle matter.

The diffusion flow shall capture the powder on the floor as much as possible and minimize the atmospheric exposure and temperature at the head level. The flow rate shall be calculated according to the expected target level of 50 % of the relevant OEL.

The air flow rate should exchange the air from top to bottom with laminar flow entry at ceiling height and extraction by grids at the floor. The Air Handling Unit (AHU) should provide 100 % of fresh air. If allowed by the legislation, energy reduction with the possibility of recycling and enslaved to the proper functioning of the absolute filtering shall be taken into account. Otherwise, an efficiency calculation shall size a heat exchanger.

A risk assessment towards collection of hazardous materials should be performed on the AHU. This risk assessment is to be used to determine the type of filtration system, if any, to be used in the AHU with the risk of fire and towards the general environment in mind.

Wherever possible, the AHU and filters should be located indoors, weather resistant and with an easy maintenance as a priority.

The polluted area can be enclosed or confined to increase the efficiency of the capture (for example, by using a suction backsplash, a suction ring, etc.). The collection air speed shall be adapted so that the collection system is able to collect the pollutant according to its nature, temperature and initial speed. In general, this collection speed is between 0,5 and 2 m/s. The transport air velocity (higher than the capture velocity) in the ducts shall be adapted to the characteristics of the pollutants transported (density, concentration, etc.). For powders, a minimum of 20 m/s is required to avoid deposits in the ducts.

An oxygen monitoring system coupled to a workplace audio and visual alarm shall be used to detect build-up or accidental release of inert gasses used in the process. This sensor should be placed near floor level (typically 0,5 m) to detect heavier than air gasses or above head level to detect lighter than air gases prior to the creation of a hazardous situation.

An underpressure between 2 Pa to 5 Pa between each autonomously managed area, with the air flow rate through the ventilation system shall be provided. The source gases removed from the source during the process should be exhausted outside after filtration and not being reused in the AM workplace.

Fire protection shall be determined in detail according to local and operational conditions. Fire prevention measures for combustible material weighing, sieving, transport, processing and post-processing operations shall be based on a combustible dust hazard analysis.

These measures shall include the provision of an emergency shutdown system with local and remote actuation devices, smoke and heat ventilation systems, as well as escape and rescue routes in compliance with national and regional standards.

NOTE 1 For detailed national fire protection requirements see e.g. NFPA 654 (US), TRGS 800 and DGUV Information 205–001 (Germany).

Agents for extinguishing classes A and B fires (according to NFPA 10 and EN 2) shown to be effective for controlling pertinent combustible-polymer fires shall be provided in areas where combustible polymer dust are present. The polymer powder safety data sheet and pertinent national regulations and standards shall be reviewed in selecting specific agents.

The supply of portable and mobile extinguishers shall be made in accordance with the local body responsible for fire protection.

Arrangements shall be made in advance with the local body responsible for fire protection to develop a comprehensive emergency preparedness plan accounting for any special reactivity hazards of the polymer being used at the facility.

NOTE 4 For additional planning details see e.g. NFPA 654 (US), DGUV-Information 205–001 (Germany).

Low voltage distribution (LV) wiring supports shall be minimized in length and dust surface. They shall be easy to clean. Holes in partition walls for pipes or cables shall be airtight.

The lighting and power outlets shall be at minimum consumption, for a required lighting level of 500 lx minimum. They shall be easy to clean.

Cable distribution in the confined area shall be sealed.

Limitations on the amount of polymer materials stored and required separations as well as material storage restrictions should be as specified in national, regional, and local building and fire codes and regulations.

The storage instruction contained in the safety data sheet shall be applied. Additionally, the following items shall be considered:

— store in a closed container to prevent possible contamination (because of dampness, dust, etc.);

— protect containers from physical damage;

— welding, grinding, or other processing that can generate heat and sparks shall not be performed close to storage areas. Smoking shall not be permitted in storage areas;

— storage containers of polymer materials shall be kept separate from other chemicals in a storage area. Those chemicals can be, but are not limited to oxidizers, fuels, etc.;

— review with local building authority for restrictions on building, storage piles, and total allowable quantities (e.g.: use of cabinet storage);

— external surfaces of containers should be kept visibly clean to minimize the potential for skin exposure and spread of contamination.

NOTE Local regulations can be more specific.

Changing rooms

Unless the risk assessment indicates otherwise, the PPE equipment room should be designed with two successive premises for clean PPE and for dirty PPE, separated by a door always closed (with alarm), obligatory passage in both directions of entry and exit:

a) Changing room for clean PPE and storage of personal effects not kept under the suit. People come in work clothes (they changed themselves before in a previous room). As a result, there is no male/female differentiation necessary for the changing room for clean PPE;

b) Changing room for dirty PPE to remove and discard all dirty PPE. This is also where the hoods should be cleaned and stored before removing the suit, and where the hands should be washed before going out. A sticky floor mat should be placed in front of the intermediate door between the two changing rooms. A shower in case of accident is preferably there or it shall be fitted in the production site.

Used PPE should be properly removed and stored to avoid contamination.

First aid

Wherever polymer dust is emitted, adequate access to eye showers should be provided for immediate relief after contact with dust. Location of eye showers shall also take into account the risk related to reactive powders. Workers exposed to polymer dust shall be trained in the use of these devices.

An adapted first aid kit shall be present in the immediate vicinity of all rooms where dust is emitted. At least two responsible workers trained in the use of first aid media shall be present at all times in the production site.

Evaluate if any risks (chemical, thermal) for the operator require the installation of a safety shower in the workshop.

Depending on the process in use and the operating phase considered, the prevention and protection measures against the risks associated with the use of polymers shall be adapted.

They can be:

— integrated into the machine during its design (capture at source, glove box, etc.);

— provided by machine peripherals (installation of general and/or workplace exhaust systems, etc.);

— located in the premises (fire suppression equipment, etc.).

The organizational measures of prevention and protection against the risks related to the use of polymer can be grouped as following:

— staff training;

— personnel information on operating procedures (including during maintenance operations);

— limitation of the number of people exposed;

— wearing personal protective equipment.

Staff shall be trained in the general risks and specific risks associated with the use of the products and by-products used.

This training shall include a presentation of the following elements:

— pictograms for chemical hazard;

— reading and understanding of labels and material safety data sheets (SDS);

— proper use of necessary PPE;

— good practices related to the use, storage and disposal of the feedstocks handled;

— first aid actions in emergency situations.

In addition to training, staff shall have access to the following information:

— instructions provided by the manufacturers of the equipment involved in the process;

— position notices, informing about the risks to which staff can be exposed and the measures taken to avoid them;

— safety data sheets (SDS);

— operational mode or other procedures and work instructions.

The number of people exposed should be the minimum required.

If required by the risk analysis, intrusion control shall consist of emergency exit doors secured by a closed door control with feedback to the operation control station and fitted with an audio alarm signal, or similar solutions having the same effect.

Unless the risk assessment indicates otherwise:

— access to the confined area shall be restricted to the strict need of operating, both in terms of personnel and equipment.

— access to the changing room for clean PPE from the outside shall be controlled by a safety device. The door between clean and dirty PPE changing rooms should be self-closing (e.g. with an hydraulic opener) and with an audio alarm signalling when opening is maintained.

After a due risk assessment carried out by the user, protective measures for reducing the exposure shall be applied according to a hierarchy that reflects the STOP principle:

— substitution (avoid the risk as far as possible, and keep remaining risks as low as possible);

— technical measures against risks, which cannot be sufficiently reduced by substitution;

— organisational measures, which cannot be sufficiently reduced by technical measures (keep people out of the hazardous area e.g. when changing filters or recovering part from bed, train and instruct those who cannot be kept out);

— personal protective measures/equipment against remaining risks.

Personal protective equipment shall be adapted to the relevant risks according to Clause 6.

Protective glasses

If the protective glasses are to be used for operation they shall be in accordance with ISO 16321-1 and ISO 16321-3, or ANSI Z87.1.

NOTE CEN/TR 13464 or ISO 19734 gives guidance for the choice of glasses.

The use of contact lenses is not recommended due to the possibility of dust getting stuck behind the contact lens.

Protective shoes

Safety footwear should either be conductive (ESD) or dissipative.

NOTE ISO/TR 18690 gives guidance for the selection, use and maintenance of safety and occupational footwear and other personal protective equipment offering foot and leg protection.

Protective gloves

Skin contact with polymer powders, can cause some reaction or irritation (e.g. dermatitis). Furthermore, in the case of small particles, the particles can penetrate the skin and become absorbed into cells in various parts of the body, including the brain. Gloves in material suitable to avoid small particle skin contamination should be worn in case of small particle exposure.

Use different gloves and glove material depending on the different operations:

— Check recommendations for the glove materials in the relevant safety data sheets.

— Use gloves while working with polymer materials (e.g. nitrile rubber with powder); make sure that the material is sufficiently thick in order to resist to the mechanical loads.

— Wear suitable chemical protection gloves when cleaning with solvents. When using isopropanol provide for nitrile rubber gloves with a thickness of at least 0,4 mm for a maximum wearing time of 8 h.

— When handling hot objects (e.g. when expanding a building plate, especially when using a pre-heating system during the construction process), provide for heat-insulating gloves.

— If support structures are removed manually, provide protective gloves with sufficient cut protection.

— Provide vibration protection gloves when using hand-held radial grinders.

Respiratory mask

Measurements of hazardous substances enable the hazardous substance load to be determined during the operations in the users' premises. Provide breathing protection unless it is ensured that concentration is below the occupational exposure limit (OEL) in all the work steps within the process chain. Select the breathing protection quality in accordance with the safety data sheet of the processed materials. Breathing protection masks may only be worn for a limited time as a rule.

Use of PPE is the least preferred control and should only be implemented if substitution, elimination, engineering, and/or administrative controls cannot sufficiently reduce exposures in 8.4.5.

NOTE Guidance for selection, use and maintenance of respiratory protective devices are contained in ISO/TS 16975‑1, ISO/TS 16975‑2 and ISO 16975‑3.

Protective clothes

The use of flame-retardant work clothing, e.g. a pocket-less overall cat. III type 5/6 (anti-static, flame-retardant according to ISO 14116) or a lab coat with corresponding properties, is recommended. Use overalls for activities with CMR substances.

Operators should use a different garment for each material to avoid cross contamination.

NOTE 1 NFPA 2112 and ISO 14116 give guidance on qualifying fire clothes for flash fire resistance. The applicability of those standards can be subject to local regulation.

Unless single-use products are used, clean protective and working clothes professionally according to a specific cleaning plan.

NOTE 2 Guidelines on the selection, use, care and maintenance of protective clothing are available in CEN/TR 15321:2006.

NOTE 3 Guidelines for selection, use, care and maintenance of chemical protective clothing are available in CEN/TR 15419:2017.

Extinguishers

The extinguising agents shall be selected according to the feedstock used and its applicable safety data sheet.

Two distinct waste streams are present when working with polymer materials:

a) contaminated filters;

b) general dry material and material scrap.

Each of these waste streams has its own hazards and is treated in a different manner, though general rules apply. In general, all hazardous material, including waste, shall be stored in an appropriately rated container. The type of container depends on the ADR or DOT classification of the waste.

Local regulation can add additional stipulations. It is highly advised to contact the local waste management provider and/or government agency for the correct regulations to be applied.

Waste material containers shall be stored in a closed off, preferably roofed, area to prevent the impact of incidents. The risk of release to the environment shall be mitigated by spill and leak containment measures, such as spill trays. The risks associated with the waste shall be marked clearly visible on the outside of the containers using standardized ADR/DOT pictograms.

The specific waste streams are addressed in 8.5.2, 8.5.3 and 8.5.4.

Polymer material based additive manufacturing machines are equipped with filters to catch fine particles and fumes. These materials can pose a fire hazard even when the bulk feedstock is not a flammable combustible. The safe removal of the filters from the equipment shall be performed according to the machine instruction handbook and a combustible dust hazard analysis for filter removal. Flash fire resistant garments and a face shield shall be used.

Dry waste can be collected from different manufacturing steps and different operations within the step. Specific risk assessments should be performed for different feedstocks (e.g. filaments, pellets).

1. 
   (normative)
   
   Safety data sheet

The safety data sheet (SDS) is the essential tool for chemical risk management. This 16-section document gives:

— explanations of the health risks related to the exposure or use of hazardous products;

— all information on handling, use or storage of products.

The SDS shall comply with the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

NOTE 1 For more details on the safety data sheet, the reader can consult the “How to read an SDS” thematic sheet at: https://vividlearningsystems.com/safety-toolbox/how-to-read-an-sds-sheet.

The safety data sheet shall be provided free of charge in paper form or in electronic form no later than the date on which the substance or mixture is first supplied (REACH Regulation, Clause 31).

All the 16 items (or sections) present in the SDS shall be read and particular attention should be paid to the following topics:

— Section 2 contains the hazard identification (toxic, CMR, ...), the hazard statements are input data for the analysis of chemical risks to health. Combustible powders can also be so identified in this section.

NOTE See 8th edition of the UN Globally Harmonized System of Classification and Labelling of Chemicals, Annex 11: Guidance on Other Hazards not Resulting in Classification

— Section 8 contains the recommended exposure limit values (OELs) and personal protective equipment (PPE). Exposure values are important data for the selection of PPE.

— Section 12 contains information useful for conducting an environmental risk analysis.

NOTE 2 Values can change with the regulations update.

The understanding of the OEL is not easy, each country may have a different value. In addition, OELs are based on scientific results, the validity of which can change over time. (see Table D.1)

NOTE 3 The REACh process has created reference values that are almost similar to OELs, but established by industry. At the current stage of regulation, only OELs are to be taken into account.

Hazardous substances (including CMR) are listed in Annex VI of the CLP Regulation, mixtures containing these substances are considered hazardous (mandatory labelling) if the content of these substances exceeds the threshold set by the regulation.

GESTIS Substance Database can be found in: https://www.dguv.de/ifa/gestis/gestis-stoffdatenbank/index-2.jsp

Information on Occupational exposure limit values (OELs) can be found in:

https://www.dguv.de/ifa/fachinfos/occupational-exposure-limit-values/index.jsp

In addition to these national information, very useful could be this site with an international character: GESTIS - International limit values for chemical agents (Occupational exposure limits, OELs):

https://www.dguv.de/ifa/gestis/gestis-internationale-grenzwerte-fuer-chemische-substanzen-limit-values-for-chemical-agents/index-2.jsp

There is a great heterogeneity within these SDSs which leads to disparities in the categories or terms used, which sometimes makes it difficult to compare one supplier to another.

1. 
   (normative)
   
   Definition of limit values
   1. General

The choice of reference shall be made after taking into account the regulations:

— regulatory values of the country of use,

— OEL values present in the REACH file and communicated by the SDS.

Then, considering references values proposed by agencies of recognized expertise, with an international impact (transcription in several countries).

• 1. Relevant agencies worldwide

ACGIH: expert association in toxicology and industrial hygiene in the USA. The ACGIH OELs have US recommendation values, and regulatory bond values in other countries, including Belgium, Spain ...

SCOEL: Expert from the European Union, in charge of recommending, on a purely scientific basis, the reference values for monitoring the exposure to chemicals in the workplace. Their recommendations, to be applied by regulation, shall be taken up by European bodies that will study the socio-economic applicability. This process is often very lengthy, which causes a lack of readability on the concrete application of the recommendation.

Reference values proposed by national agencies of experts, countries recognized for the quality and the number of their works:

a) ANSES, France.

b) BAuA, Germany,

c) STAMI, Norway.

WHO has priority public health objectives. The protection of public health implies the consideration of different parameters of worker protection, so WHO's recommendations are most often to be placed in this context in order to be interpretable and usable. For example, WHO considers night work as carcinogen. This classification is based on studies showing a link between breast cancer and low daylight exposure for night shift nurses.

In this hierarchy of sources, it is necessary to add the consideration when it is communicated, transparency on the calculation of the development of the OEL.

The statement of a reference value has two phases: the choice of the starting point, which gives a dose compared to an observed effect. The security factor application to this “starting point”. Most often, there is unanimity or clear discussion about the choice of “starting point”, and differences arise from the calculation and application of safety factors.

1. 
   (normative)
   
   Hazards related to fire and explosion
   1. General

This annex deals with fire and explosion hazards which can occur in an additive manufacturing workshop.

• 1. Material combustibility

Table C.1 gives standardized methods to determine polymer dust combustibility:

Table C.1 — Standards in reference for tests of material combustibility

It is permissible to assess dust explosibility properties using reported property data obtained via standardized tests for dust samples of the same polymer composition and particle size distribution.

NOTE 2 UN Recommendations on the transport of dangerous goods: model regulations — Manual of tests and criteria, Part III, 33.2.1 gives guidance for testing of powder layer flame propagation tendency.

The recovered dust would need to be tested before dismissing postprocessing and filter handling combustibility hazards.

• 1. Ignition source control

Build cycles where combustible dust are exposed to elevated temperature energy sources shall be performed in an inert atmosphere at an oxygen concentration below the Limiting Oxygen Concentration (LOC) for the combination of polymer dust emitted and inert gas being used. These LOC values can be determined from standard test methods such as described in ASTM E2931 or EN 14034‑4.

All separate components of fixed and connected equipment transporting or processing combustible powders are grounded and bonded. Bonding and grounding connections shall be verified prior to the transfer of powder.

Personnel handling open containers of powders or dusts with MIE values less than 30 mJ are bonded to the containers and grounded. Personnel cleaning such containers and equipment are also bonded and grounded, and wear static dissipative garments and shoes. Non-conductive containers with such powders, including shipping containers, shall be static dissipative.

Equipment operating manuals shall clearly identify all ignition sources and control measures for preventing ignition of combustible powders and dusts. Equipment manufacturers offer training in safe operation of equipment and required operating personnel safeguards to prevent fires and explosions. Only personnel trained may be allowed to operate additive manufacturing and peripheral equipment handling combustible powders.

1. 
   (informative)
   
   Overview of OEL for substances

Table D.1 gives an overview of known national OELs that have been considered relevant at the time when this standard has been drafted. It is especially intended for users in countries where no specific OELs have been set by the competent authorities, and it does not claim to be complete. In addition, OELs might have been modified since this standard has been published. Only a cross-check with national regulations containing the pertinent OELs for the country concerned can give users the certainty to actually comply with national prescriptions. For more information on OELs see also Annex A and Annex B.

Table D.1 — Examples of OELs for some substances

Flammability and explosibility depend on the powder size, morphology, additives, surface passivation and type of material. Consult the SDS for the minimal ignition temperature (MIT), Minimum ignition energy (MIE) and limiting oxygen concentration (LOC) to assess the potential hazard level.

Bibliography

[1] ISO/ASTM 52903‑1:2020, Additive manufacturing — Material extrusion-based additive manufacturing of plastic materials — Part 1: Feedstock materials

[2] ISO 6184 (all parts), — Explosion protection systems

[2] ISO 12100, Safety of machinery — General principles for design — Risk assessment and risk reduction

[3] ISO 14116, Protective clothing — Protection against flame — Limited flame spread materials, material assemblies and clothing

[4] ISO 18158, Workplace air — Terminology

[5] ISO 19734, Eye and face protection — Guidance on selection, use and maintenance

[6] ISO/TS 16975‑1, Respiratory protective devices — Selection, use and maintenance — Part 1: Establishing and implementing a respiratory protective device programme

[7] ISO/TS 16975‑2, Respiratory protective devices — Selection, use and maintenance — Part 2: Condensed guidance to establishing and implementing a respiratory protective device programme

[8] ISO 16975‑3, Respiratory protective devices — Selection, use and maintenance — Part 3: Fit-testing procedures

[9] ISO/TR 18690, Guidance for the selection, use and maintenance of safety and occupational footwear and other personal protective equipment offering foot and leg protection

[11] ISO/IEC 80079‑20‑2:2016, Explosive atmospheres — Part 20-2: Material characteristics — Combustible dusts test methods

[12] EN 2, Classification of fires

[13] EN 481, Workplace atmospheres — Size fraction definitions for measurement of airborne particles

[14] EN 14034‑1, Determination of explosion characteristics of dust clouds — Part 1: determination of the maximum explosion pressure pmax of dust clouds

[15] EN 14034‑2, Determination of explosion characteristics of dust clouds — Part 2: determination of the maximum rate of explosion pressure rise (dp/dt)max of dust clouds

[16] EN 14034‑3, Determination of explosion characteristics of dust clouds — Part 3: determination of the lower explosion limit LEL of dust clouds

[17] EN 14034‑4, Determination of explosion characteristics of dust clouds — Part 4: determination of the limiting oxygen concentration LOC of dust clouds

[18] CEN/TR 13464, Guide to selection, use and maintenance of occupational eye and face protectors

[19] CEN/TR 15321, Guidelines on the selection, use, care and maintenance of protective clothing

[20] CEN/TR 15419, Protective clothing — Guidelines for selection, use, care and maintenance of chemical protective clothing

[21] ASTM E1226, Standard Test Method for Explosibility of Dust Clouds

[22] ASTM E2019, Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air

[23] ASTM E2931, Standard Test Method for Limiting Oxygen (Oxidant) Concentration of Combustible Dust Clouds

[24] NFPA 10, Standard for Portable Fire Extinguishers

[25] NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids

[26] NFPA 2112, Standard on Flame-Resistant Clothing for Protection of Industrial Personnel Against Short-Duration Thermal Exposures from Fire

[27] REACH, Registration, Evaluation, Authorization and Restriction of Chemicals

[28] TRGS 800, Fire protection measures — Technical Rule for Hazardous Substances

[29] DGUV information 205-001, Operational fire protection in practice