What Activity Categories Should Be Evaluated During Process Flow Analysis? Eliminate Pilot Plant Waste

Evaluate five activity categories during pilot plant process flow analysis: operations, transportation, inspection, storage, and delays. Operations usually contain the primary value-adding work, such as reaction, distillation, filtration, mixing, heating, or separation. The other categories should be measured carefully because unnecessary transport, redundant inspections, excessive storage, and unplanned waiting often create non-value-added operational time.

A process flow analysis should classify every pilot plant activity into these five categories, then quantify its duration and purpose. The goal is to protect essential operations while removing avoidable movement, waiting, duplicate control steps, and inefficient workflow design.

The Five Categories to Evaluate

Operations

Operations are the core activities that transform materials or change their physical or chemical state. Examples include reaction, heating, mixing, filtration, distillation, drying, and separation.

These steps are typically value-adding, but they should still be assessed for setup time, rework, downtime, and sequencing inefficiencies.

Transportation

Transportation covers the movement of fluids, solids, reagents, samples, equipment, and information between process stages. Physical transfers may occur through piping, hoses, vessels, carts, or manual handling.

Information transfer also belongs in this category, including moving test results, batch records, or operating instructions between teams or systems.

Unnecessary transfers between modules, excessive hose connections, manual equipment transport, and repeated data entry are common sources of non-value-added time.

Inspection

Inspection includes sampling, analytical testing, measurement, quality checks, sensor verification, pressure checks, and safety inspections.

Some inspections are essential controls and must remain. The analysis should identify redundant tests, duplicate data collection, excessive sampling, and inspections that could be performed in parallel with another activity.

Storage

Storage is planned or scheduled holding of materials, intermediates, samples, or batches. Examples include batch accumulation, hold tanks, buffer vessels, and scheduled material staging.

Storage is not automatically wasteful. It may be required for process stability, safety, batch control, or equipment scheduling, but unnecessary intermediate storage can extend cycle time and increase handling requirements.

Delays

Delays are unplanned waiting periods caused by unavailable equipment, operator constraints, missing materials, maintenance, resource bottlenecks, approval requirements, or process interruptions.

Unlike planned storage, delays do not serve an intended process function. They are usually the clearest indicator of avoidable non-value-added time.

How the Categories Reveal Waste

Separate Value-Adding Work From Control Activities

A useful process activity chart can assign value codes to each activity:

Value-adding (V): Transformation that contributes directly to the experimental or production objective.
Non-value-adding (N): Waiting, unnecessary transfers, avoidable handling, or redundant steps.
Control (C): Inspections, safety checks, measurements, and quality-control activities.

This classification prevents essential inspections from being incorrectly treated as waste while still exposing controls that are duplicated or poorly timed.

Measure Duration and Frequency

Record the time spent on every activity, not only the major unit operations. A short delay repeated across many runs may consume more total time than a single long inspection.

The analysis should also capture how often an activity occurs, whether it is performed sequentially or in parallel, and whether it causes rework or additional waiting.

Trace the Critical Path

Serial activities accumulate into total cycle time, while compatible activities can sometimes run concurrently. The effective process duration is governed by the longest critical path rather than simply by the sum of all activity durations.

This makes it important to identify which transport, inspection, storage, or delay activities directly extend the critical path.

Where Non-Value-Added Time Commonly Appears

Unnecessary Transportation

Long distances between modules, poorly arranged equipment, and repeated manual transfers increase handling time and the risk of contamination, spills, or connection errors.

Reconfiguring equipment or improving transfer routes can reduce this time without changing the underlying process.

Redundant Inspections

Repeated sampling or testing may result from unclear acceptance criteria, poor process control, or a lack of confidence in earlier measurements.

Inspections should be retained when they support quality or safety, but their timing and frequency should be reviewed to determine whether some can be combined, automated, or performed concurrently.

Unplanned Delays

Waiting for an operator, instrument, material, approval, or available vessel directly reduces operational uptime.

Scheduling improvements, reduced setup time, reliable equipment availability, and better coordination between activities can address these delays.

Rework and Re-Inspection Loops

A failed parameter check may trigger repeated processing, additional sampling, or another full inspection cycle.

Improved operating procedures, parameter control, and first-pass quality reduce these loops and prevent non-value-added time from being embedded in the normal workflow.

Understanding the Trade-offs

Essential Controls Cannot Be Removed Arbitrarily

Safety inspections, pressure checks, quality tests, and regulatory records may not add direct physical value, but they can be necessary control activities.

The objective is to eliminate unnecessary control work, not to bypass safeguards or weaken product and operator protection.

Planned Storage May Be Necessary

Hold tanks and batch accumulation points can support continuous operation, process stability, or safe sequencing.

Removing storage without understanding its purpose may create equipment conflicts, unstable processing, or unsafe operating conditions.

Parallel Work Requires Compatibility

Running sample preparation, reference checks, or parallel reactions concurrently can reduce cycle time.

However, parallel execution is appropriate only when activities do not compete for the same equipment, violate safety requirements, or depend on results that are not yet available.

Training Needs May Affect Efficiency

Educational pilot plants may require manual demonstrations or additional checks that would be streamlined in an industrial facility.

These activities can still be justified when they support learning, but they should be distinguished from process requirements so that training time is not mistaken for unavoidable production time.

Making the Right Choice for Your Goal

Use the five categories as a complete activity inventory, then prioritize improvements according to the pilot plant's main objective.

If your primary focus is reducing cycle time: Target unplanned delays, unnecessary transportation, redundant inspections, and rework loops that extend the critical path.
If your primary focus is increasing operational uptime: Improve equipment availability, scheduling, setup procedures, and resource coordination.
If your primary focus is maintaining quality and safety: Preserve necessary control activities while removing duplication and improving their timing.
If your primary focus is improving training efficiency: Document value-adding, non-value-adding, and control activities separately so instructional tasks remain purposeful and measurable.

By classifying every activity as operation, transportation, inspection, storage, or delay, pilot plant teams can reduce avoidable time while preserving essential process and safety functions.

Summary Table:

Activity category	What to evaluate	Common non-value-added issue
Operations	Reaction, heating, mixing, filtration, distillation, and separation	Setup time, downtime, rework, or poor sequencing
Transportation	Movement of materials, samples, equipment, and process information	Excessive transfers, hose connections, or manual handling
Inspection	Sampling, testing, measurement, and safety checks	Duplicate tests, excessive sampling, or poor timing
Storage	Holding tanks, intermediates, samples, and staged materials	Unnecessary accumulation or extended hold time
Delays	Waiting for equipment, operators, materials, approvals, or maintenance	Bottlenecks, interruptions, and resource constraints

Need to reduce cycle time, improve uptime, or optimize training in your pilot plant? Contact LABPARK to discuss your requirements. LABPARK provides Educational and Vocational Unit Operations Pilot Plants for chemical engineering, bioprocess and biotech, and environmental and water treatment applications. Our solutions help universities, research institutes, and enterprises evaluate process workflows, identify non-value-added activities, strengthen practical training, and improve equipment utilization while preserving essential quality and safety controls.