Before digital tools and AI-driven analytics, one British standard quietly shaped how the world measures human work: BS 3138. Established in the mid-20th century, BS 3138 provided a systematic method to evaluate manual work cycles using Time Study principles. Its introduction revolutionized how industries across manufacturing, logistics, and services measured labor productivity. While newer tools have emerged, the core logic of BS 3138 still underpins many modern lean practices and industrial engineering techniques. 

In this blog, we explore what BS 3138 is, why it matters, and how its legacy continues to influence operations today.

What Is BS 3138?

BS 3138, issued by the British Standards Institution (BSI), defined the use of Time Measurement Units (TMUs) and established a consistent, objective framework for conducting time studies. One TMU equals 0.0006 minutes or 0.036 seconds—small enough to capture even micro-movements in a manual task.

The core idea was to eliminate subjectivity in work measurement by breaking down tasks into basic motions—grasp, move, position, release—and assigning standardized TMUs to each. This allowed industrial engineers to estimate task times without needing repeated observations or stopwatch-based time studies.

BS 3138 included:

• A classification of basic movements
• TMU values for each movement
• Guidelines for evaluating work under “normal” performance conditions
• Adjustments for skill, effort, and fatigue

This standard became a cornerstone for methods-time measurement systems like MTM-1 (Methods-Time Measurement) and later, more specialized systems like MTM-2, MOST, and MODAPTS. It also helped ensure fairness in setting labor standards, reducing bias in piece rates and productivity assessments.

Why BS 3138 Still Matters Today?

While the era of clipboards and stopwatches has faded, the principles of BS 3138 are more relevant than ever—especially in digital manufacturing and workforce optimization.

Here’s why BS 3138 still holds value:

• Standardization of Human Motion: The breakdown of tasks into elemental movements helps identify inefficiencies in manual work. This is crucial for lean manufacturing, where waste elimination is paramount.
• Fair Labor Standards: By establishing “normal” performance benchmarks, BS 3138 created a more equitable system for evaluating worker performance—something modern labor relations still grapple with.
• Foundation for Automation Logic: Many robotic task-planning algorithms use motion breakdowns similar to BS 3138. Understanding the standard helps bridge human and machine task planning.
• Digitization Compatibility: Tools like MOST and MODAPTS, built on BS 3138, are now integrated into digital platforms for work analysis, standard setting, and ergonomics. This makes legacy knowledge compatible with modern systems.

For Example:

An electronics assembly plant digitized its standard work using MTM-based software. By referencing BS 3138-derived TMU values, they identified tasks that could be reengineered for speed or ergonomics. The result? A 12% productivity increase with no additional automation.

Moreover, BS 3138 indirectly supports continuous improvement in Manufacturing. By making the invisible visible—those tiny wasted motions—it empowers teams to redesign work with precision.

How to Apply BS 3138 Principles in Modern Continuous Improvement Efforts

Even though BS 3138 was developed in a pre-digital era, its structured approach to analyzing human work remains incredibly useful for today’s continuous improvement (CI) leaders. The core idea—breaking down manual tasks into standardized motions and measuring them consistently—translates well into digital lean tools, ergonomics assessments, and automation planning.

Here’s how to bring the spirit of BS 3138 into the modern CI landscape:

1. Adopt Motion Analysis Software Built on TMU Principles

Manual stopwatch time studies are no longer the gold standard. Instead, software platforms built on MTM (Methods-Time Measurement), MOST (Maynard Operation Sequence Technique), and MODAPTS (Modular Arrangement of Predetermined Time Standards)—all of which trace their roots to BS 3138—now allow teams to analyze work in far more detail and with much less bias.

Explore more about What is Methods-Time Measurement in our blog. The blog has also covered a detailed comparison between MTM vs. MODAPTS. 

These tools can:

• Analyze video recordings of work and break them into elemental motions (reach, grasp, move, release)
• Apply predefined TMU or time values to each motion
• Identify unnecessary steps, awkward reaches, or unsafe movements

This not only accelerates the time study process but also ensures repeatability and objectivity. Teams no longer need to rely on individual experience to judge what “normal” work looks like.

2. Standardize Before You Optimize

One of the most overlooked lessons from BS 3138 is that standardization precedes optimization. If you haven’t clearly defined what the work should look like, you can’t make meaningful improvements.

In practice, this means:

• Breaking down each task into discrete motions using standard templates
• Defining the correct sequence, orientation, and tools for each motion
• Capturing this as the “baseline” for cycle time and performance

Once this motion-level standard is in place, you can start identifying:

• Which steps can be eliminated or combined
• Where delays or micro-delays are creeping in
• What tasks are ripe for automation or tool redesign

3. Digitize and Distribute Standard Work Instructions

Modern CI tools allow motion-level standards to be embedded into digital work instructions. Rather than handing workers a paper SOP, you can give them tablets or screens with interactive, step-by-step guidance based on the optimal sequence of motions.

The best tools:

• Show each step visually (photos, videos, or annotated diagrams)
• Highlight time expectations for each motion or task
• Include built-in feedback loops for operators to flag when real-world steps deviate from standard

By linking motion-based standards to frontline execution, you move from theory to practice—ensuring that the standards derived from BS 3138-style analysis are not just documented, but actively used and improved upon.

4. Use Motion Data to Improve Ergonomics and Safety

BS 3138 doesn’t just help with productivity—it also enables ergonomic risk analysis. Repetitive strain, excessive reaching, awkward postures, and high-frequency motions can all be detected early by analyzing motion patterns.

CI leaders can collaborate with safety or ergonomics teams to:

• Redesign workspaces to reduce excessive motion
• Rotate tasks based on physical intensity
• Implement assistive devices where needed

This helps reduce workplace injuries and improves long-term workforce sustainability—both critical elements of operational excellence.

5. Connect Motion Standards to Key Performance Indicators (KPIs)

Finally, you can tie motion-level analysis directly into broader performance metrics. Once you know the optimal motion sequence and its TMU-based cycle time, you can set more realistic and data-backed KPIs.

Use this approach to:

• Set takt time targets aligned with real work capability
• Estimate capacity per shift or per operator
• Calculate the labor content of each product variant
• Measure deviation from standard during audits or Gemba walks

In short, BS 3138-style thinking gives you a microscopic lens that helps make sense of macroscopic outcomes—like throughput, utilization, and efficiency.

Measure Operational Excellence with Key Metrics and KPIs for ensuring continuous improvement in your smart factory. Refer to our blog that has listed the important KPIs and key metrics and how to calculate with them. 

Conclusion

BS 3138 laid the groundwork for precise motion analysis and labor standards—but applying it today requires modern tools. Solvonext brings those principles into the digital age, making it easy to standardize work, analyze motion-level tasks, and set data-driven performance targets. 

With built-in support for time-study logic, digital SOPs, and ergonomic insights, Solvonext helps you reduce waste, improve consistency, and boost frontline efficiency—all without the complexity of manual analysis. Whether you're optimizing a workstation or scaling best practices across sites, Solvonext turns BS 3138’s legacy into a powerful advantage for modern continuous improvement. Start optimizing with precision—start with Solvonext.

Book a demo today!