Engineering Requirements Document: Useful Tips for Writing

To execute a successful engineering project, creating an engineering requirements document is necessary. This essential blueprint serves as a guide that explains what a project entails and the conditions and functionalities that must be met.

In this post, you will learn how to write a practical ERD sample, the criteria for writing a good requirement document, and lots more.

What is an Engineering Requirements Document (ERD)?

An engineering requirement document is a vital, structured statement or document detailing the criteria or requirements to which a system or project must conform to achieve its objective.

They serve as a blueprint outlining the features, specifics, and functionalities of a project.

Engineering requirement documents are essential tools because they serve as a guide for every stakeholder involved in an engineering project, ensuring that everyone understands what the project entails, the goals to be achieved, and how it should be carried out.

Purpose and Importance of ERDs

The importance of an engineering requirement document while planning and implementing an engineering project cannot be overemphasized. Here are some reasons to consider designing an ERD for your next project.

Provides More Clarity

With an ERD, you and every other stakeholder involved in the project get a clear representation of what the project entails.

ERD details the project objectives, constraints, functionalities, and conditions, ensuring that misunderstanding is reduced to the barest minimum.

Serves as a Guide

An effective ERD helps you understand what is expected during the project implementation. It helps provide a direction for which the project implementation would follow.

It serves as a guide for the project managers, engineers, and every team member, ensuring that decision-making processes are carried out as planned.

Ensures Quality Assurance

Since they are seen as a road map and blueprint for engineering projects, you can easily use ERD to test the project quality. As such, you'll be able to check if the final output meets the specific criteria and requirements outlined in the document.

Explains the Project Scope

By using an ERD, you and your team members will be able to comprehend the scope of the project and stay within the boundaries of the scope. With this, you will be able to achieve the project objectives while also effectively maximizing the time and budget factor.

Serves as Basis for Project Evaluation

You will be able to ascertain if the objective of each project milestone has been achieved or not. This will, in turn, guide towards achieving the overall project's goal.

Ensures Adequate Communication

ERDs also help ensure that there is effective communication among every party involved in the project.

As the project manager or engineer, you do not have to always explain what’s expected before, during, and after project execution to other members involved. With an accurate requirement document, everyone stays updated and informed.

Components of an ERD

A typical ERD consists of the following components:

Project Overview

This is the section where the project is introduced. You will need to outline the scope and goals of the project here, together with the target audience.

Exigences fonctionnelles

Here, you will detail the features and functions to which the project must adhere. This section explains what the project or system must do, including the specific functionalities that it must meet.

Non-Functional Requirements

Non-functional requirements explain factors relating to quality, usability, performance, reliability, security measures, and characteristics of the project, etc.

Assumptions

These are relevant factors that might be considered valuable for the purpose of the project, but might later be subject to change.

Contraintes

These are potential limitations that might be faced, and they include resources, funds, time, technological inputs, etc.

Revision Log

The revision log is a component that contains every change made to the documents. It helps ensure that all members are aware of every update made in the document.

Criteria for Good Engineering Requirements Document

When creating your ERD, you should adhere to some essential criteria to ensure that the document is relevant and serves its purpose. Below are some ERD requirements to note.

Clear and Comprehensive

Firstly, you must ensure that the requirement document is written in simple, easy-to-understand language such that every member comprehends it properly. It should also be written in a well-arranged manner, following a given template and highlighting every component.

Verifiable

For every requirement documented, there must be ways to gauge if they are actually verifiable or testable; that is, you must provide only requirements that can be tested for successful execution.

Traceable

Your ERD must also contain components that are easily relatable or traceable to the main project's goal. With this, you will be able to ascertain the importance of every section to the project's purpose.

Beyond that, it must also be traceable or relevant to the customer’s needs, ensuring that every requirement meets their expectations.

Feasible

Feasibility is vital when creating this vital statement. You should add only achievable requirements, taking into consideration the available resources, finance, time, legal constraints, and every other factor possible.

Doing this will help ensure a smooth delivery of the project while also minimizing complications.

Necessary

A good engineering requirement document should contain every necessary detail. It should be comprehensive enough without the omission of important factors and points. On the other hand, it must also contain only the necessary points that are targeted towards the purpose and scope of the project.

Coordinated

ERD must be accurate and correct throughout the development and execution process. It should give a clear detail of the conditions, project requirements, goals, etc.

Complete

Every vital detail must be included to ensure completeness. All requirements must be detailed properly to avoid omissions. This will, in turn, help ensure that every step and action is taken during execution.

8 Tips for Writing an Engineering Requirements Document

Identify and Engage Stakeholders

When writing an engineering requirement document, it is vital to identify every party that will be involved in the project. These include the engineers, clients, designers, users, and so on, who are actively interested in the project output.

Engaging them right from the onset helps ensure that everyone's perspective is captured and expectations and needs are met.

Gather and Define Requirements

Here, you will need to engage the stakeholders either through interviews, meetings, surveys, workshops, or any other form of information gathering to determine the requirements to be included.

When making final decisions on the requirements to add, remember to follow the seven criteria explained earlier. Also, define the requirements into functional and non-functional.

Use a Good Template

Importantly, you should use a well-structured template for your requirement document. This will help ensure that you stay organized and that no section or component is missed.

A good template should consist of all the components of ERD explained earlier.

Use Best Formatting Practices

While crafting your ERD, it is best to maintain the best formatting practices. This will help ensure that every stakeholder easily comprehends the document whenever they read it. You should do the following when formatting the document:

• Choose a particular font style and size and maintain it throughout.
• List and bullet points when necessary
• Provide Clear headings
• Use tables, diagrams, and images when needed

Be Consistent with the Use of Imperatives

Although there has been a lot of argument on the right use of imperative words like shall, may, will, etc, the best option will be to adhere to the standards set by your organization for the use of these terms.

Several stakeholders, however, had always used shall as a binding provision and may and should as non-binding provisions.

Adhere to a Concise Identification System

Labelling every requirement with a unique identifier makes traceability and referencing easy. Usually, an identifier includes the project code, requirement number, and version number.

The project code is attached to every project, requirement numbers are sequentially used to tag each requirement, while version numbers are used to trace changes and updates made.

Provide an Operational Definition of Terms Used in the Documents

To provide more clarity to your document, you should define some specific words and terms used.

Just like a single word in the English Language could connote several meanings depending on the context in which it is used, some specific terms used in the ERD may also represent multiple meanings.

To avoid causing confusion or misinterpretation, it is best to design a section that operationally defines or explains each term as used in the document. This way, everyone would be on the same track and interpret the document the same way.

Review and Update Necessary Changes

Lastly, you should do a thorough check for accuracy, grammatical alignment, and completeness. Ask for a review from other stakeholders involved and make necessary changes. Also, every update made during the course of the project should be included in the ERD.

Engineering Requirements Document Sample

Project Overview

Project Name: Automated Bottle Filling Machine

Purpose: To develop an automated bottle-filling machine to maximize efficiency and performance when filling liquids into bottles in an industrial setting.

Scope: The project seeks to design an advanced, automated bottle-filling system that can work with high speed and efficiency with little to no human supervision.

Functional Requirement

Vitesse

• The machine must fill up to 25 bottles of at least 250ml each per minute.
• It must automatically fill the bottle without any supervision

Efficacité

• Avoid liquid spills by using accurate precision nozzles.
• It must be able to detect bottle presence and position them well

Non Functional Requirement

Performance

• The machine must work effectively at a minimal noise level below 55 decibels
• It must maintain an accurate bottle volume filled based on set measurements.

Sécurité

• Must include automatic emergency stop and safety panels
• It must comply with the local and national authority safety standards

Assumptions and Constraints

Timeline

The actual machine design and prototype should be completed within a year.

Revision log

The first edition was created on 24th June 2025.

Benefits of a Well-Structured ERD

Creating a well-defined and structured ERD is necessary because of the benefits it offers. Here are some of them you should know.

Enhances Project Management

With clear and comprehensive ERDs, you get to understand the details of the project. By so doing, it becomes easier to allocate the needed resources, funds, and time, thereby ensuring an excellent project output.

Facilitates Effective Task Delegation and Collaboration

A well-structured ERD outlines tasks in a given project. With this, you can easily delegate responsibility to every party and also encourage collaboration among members when needed.

Mitigates Against Risks

With a properly structured document, you can easily foresee a potential risk or constraint. By paying close attention to such conditions, you can develop techniques to avoid the risk and work more effectively.

Increases Efficiency and Effectiveness

You can also expect a greater level of work effectiveness and efficiency with a clearly planned-out ERD.

Since the document acts as a direction to follow, you can easily avoid errors and mistakes by executing the project as outlined in the ERD requirement.

Ensures Customer Satisfaction

A good ERD also helps you understand your client’s needs. With this, you’ll be able to deliver an output or project that meets the client's expectations. By doing so, it becomes much more feasible to achieve customer satisfaction and build trust.

Facilitates Effective Documentation

Proper and effective documentation of every engineering project within a company is crucial. Not only will this serve as a point of reference for the decisions made regarding projects previously done, but it can be a valuable tool for another similar project to be carried out next.

A good way to ensure adequate documentation of engineering projects is to design an accurate and well-structured ERD.

Tools and Standards for Managing Requirements

Managing engineering requirements and following some specific standards is vital to effectively executing a project. Here are some tools you might want to consider for your requirement management.

Requirement Management Tools

This allows you to track, record, and manage requirements throughout the project execution stages. Polarion requirements and JIRA are good examples here.

Version Control Systems

With version control systems, you can manage every new update of the requirement by keeping track of and maintaining it. Tools like Git and Subversion are found here.

Diagramming Software

Diagramming tools allow you to input diagrams, charts, tables, and other visual representations into your requirements. It includes MS Vision and Lucidchart.

Document Collaboration Tools

This software allows several people to access, collaborate, and work on the ERD at the same time. With it, you can edit and share the requirement document with other members. It includes Google Docs and MS SharePoint.

Product Requirement Documents PRD to Engineering Requirement Document ERD Translation Table.

If you are familiar with a PRD, then you can translate sections from it to specific components within the ERD. Here are some features within the PRD that are translated to their equivalent ERD sections.

Conclusion

Writing a good ERD involves following a specific template, engaging other stakeholders, ensuring that it meets the criteria explained above, and so on.

Beyond crafting an accurate ERD, you need high-quality materials to help bring the next project idea to life. At DEK, we specialize in producing durable, top-notch materials that suit every one of your engineering project needs. Whether you need expert advice or guidance or a reliable and stable supplier, do reach out to us today.