Before the introduction of Annex SL in 2012, obtaining multiple ISO certifications was often complex and challenging for organizations. This guide outlines the structure and its significance for ISO standards.
Annex SL is commonly known as High-Level Structure (HLS). However, as of 2021, this term has been formally replaced by ‘Harmonized Structure’ in the ISO/IEC Directives.
What Is Annex SL?
Annex SL is a set of rules developed by the International Organization for Standardization (ISO). It ensures that new and revised ISO management system standards share a common structure, terminology, and definitions.
This alignment means that whether an organization is working with standards for quality, environment, or health and safety, the basic layout and many key terms are consistent.
Previously, each ISO management system standard had a unique structure and language, making it more difficult for organizations to implement multiple standards simultaneously.
For example, an organization following both ISO 9001 (Quality Management) and ISO 14001 (Environmental Management) would have encountered different structures and terminology, even for similar requirements.
Annex SL addresses this with a unified structure.
What Is the Annex SL Structure?
Annex SL provides a unified structure for ISO management system standards, with new and revised standards sharing a common structure, terminology, and definitions.
This alignment makes it easier for organizations to work with multiple ISO management system standards such as ISO 9001, ISO 14001, ISO 27001, and ISO 45001.
It helps to reduce complexity, align management systems with overall strategy, and improve operational efficiency. This supports compliance, helping to reduce risk and enhance market access.
How Does Annex SL Improve the Quality of ISO Standards?
ISO is a global body that develops voluntary standards for products and services. The goal of ISO standards is to reduce barriers that organizations may face when selling their products and services either in different markets or to different customer groups.
With Annex SL, organizations adopting multiple management system standards benefit from a unified structure, which may help to make integration more straightforward.
It improves the quality of ISO standards in several important ways:
- Consistency: By providing a common structure and set of terms, Annex SL helps ISO management system standards remain consistent, making them clearer and more predictable for organizations.
- Integration: Organizations can more easily combine different management systems. This integrated approach can lead to more efficient processes and better overall performance.
- Reduced complexity: Annex SL helps to eliminate confusion and duplication caused by differing structures and language in older standards. This means organizations spend less time trying to interpret requirements and more time actually improving their systems.
- Alignment with business goals: Because the standards are now based on a similar structure, it’s easier for organizations to align their management systems with their overall strategy and objectives.
What Benefits Will Businesses See as a Result of Using Annex SL–Based Standards?
Certification to Annex SL-based standards such as ISO 9001, ISO 14001, ISO 27001 and ISO 45001 may offer organizations a range of operational and compliance benefits.
Maintaining compliance with one or more of these standards could help a business reduce its operating risk, improve operating efficiencies, support cost management, and enhance customer and employee satisfaction.
Certification may also enable organizations to access new markets and business opportunities, particularly in regulated industries that require assurance of an organization’s products, processes, and operating controls.
A significant benefit of Annex SL is that, due to the shared structure, adopting additional standards becomes much more straightforward and could be less costly.
Example: Before and after Annex SL implementation
Imagine a construction company aiming to become certified to both ISO 9001 and ISO 14001.
Before Annex SL:
Each standard used different structures and language. The team would need to create separate procedures, documents, and training for each one.
After Annex SL:
Both ISO 9001 and ISO 14001 now follow the same structure and use similar terms. The organization can integrate its processes, use combined documents, and run joint training and audits.
This makes it easier to manage both standards, saving time, and allowing the business to focus more on continual improvement and less on paperwork.
Common Annex SL FAQs
Does Annex SL affect existing ISO standards that were published before its introduction?
Annex SL was first published in 2012. Existing standards published prior to Annex SL do not automatically change; however, as these standards come up for their regular review and revision cycles, they are updated to align with the Annex SL structure and terminology. This allows for a gradual transition, ensuring organizations benefit from a harmonized approach as standards are revised over time.
Can small businesses benefit from Annex SL, or is it only useful for large organizations?
Annex SL is designed to be scalable and accessible, offering benefits to organizations of any size or type. For SMEs, the ability to integrate multiple management systems using a common structure can result in savings of time and resources, and can simplify training, documentation, and audits.
How does Annex SL handle industry-specific requirements?
Annex SL provides a high-level structure that serves as a foundation for all management system standards, but it is intentionally flexible. While the core clauses remain the same across standards, each ISO standard can add sector or discipline-specific requirements, as necessary. This means the backbone is consistent, but the structure still addresses specialized needs.
Will adopting standards aligned by Annex SL change how audits are conducted?
The alignment of standards through Annex SL can lead to more streamlined and efficient audits. Because the structure and many requirements are now shared, organizations may be able to combine audits for different management systems, reducing duplicate effort.
Are there any criticisms or limitations of Annex SL?
Some industry experts and organizations feel that the high-level structure can sometimes be too generic, leading to standards that may not fully address the unique needs of highly specialized sectors. However, ISO technical committees have the flexibility to add sector-specific content as needed, and the overall consensus is that the benefits of Annex SL outweigh these potential drawbacks.
Can Annex SL be applied outside of ISO standards?
While Annex SL was specifically developed for ISO management system standards, its principles—such as standardizing structure and terminology—can be valuable for organizations looking to improve their own internal procedures. Some organizations have adopted the Annex SL model as the best practice to streamline management, even for systems not formally certified to an ISO standard.
Does Annex SL impact the documentation requirements for management systems?
Annex SL does not specify exactly what documents an organization must produce, but it encourages a process-based approach rather than a documentation-heavy one. This shift allows organizations to create more integrated and efficient documentation systems, reducing unnecessary paperwork.

