working capacity calculation for the equipment in pharmaceuticals

 

1. Identify Equipment Capacity from URS/Manual

• Check manufacturer’s datasheet or URS (User Requirement Specification) – it gives total capacity/volume/weight handling capacity (e.g., blender 500 L, FBD 60 kg, compression machine 40 stations, etc.).

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2. Apply Working Capacity Factor

• For GMP, we never use 100% of design capacity because of safety, mixing efficiency, and process performance.
  Typical industry thumb rules:

• Blender (double cone, V-blender, bin blender): 50–70% of gross volume

• Fluid Bed Dryer (FBD): 40–60% of rated volume (depends on bulk density, airflow)

• Granulator / RMG: 60–80% of total volume

• Compression Machine: Capacity depends on turret speed × no. of stations × tablet weight

• Coating Pan: 60–70% of pan volume

• Autoclave: 70–80% load of chamber volume (based on load configuration)

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3. Calculate Working Capacity

• Formula (for volume-based equipment):

  $$\text{Working Capacity (kg)} = \text{Gross Volume (L)} \times \text{Bulk Density (kg/L)} \times \text{Utilization Factor (0.5–0.8)}$$

• Example – Blender 500 L:

  • Bulk density = 0.5 kg/L

  • Utilization factor = 0.65

  • Working capacity = 500 × 0.5 × 0.65 = 162.5 kg

• Example – Compression Machine 27 stations:

  • Output (tablets/min) = (No. of stations × turret rpm)

  • If 27 stations, 30 rpm → 27 × 30 = 810 tablets/min

  • If tablet weight = 500 mg → 810 × 0.5 g = 405 g/min ≈ 24.3 kg/hr

4. Cross-check with GMP Guidelines

• Don’t exceed validated batch size during routine manufacturing.

• Validation studies determine min and max working capacity (e.g., 30–60% of design).

5. Over decades, pharma industries standardized practical utilization ranges:

• Blenders: 50–70% (to allow powder movement)

• Granulators: 60–80% (to allow impeller & chopper action)

• FBD: 40–60% (for air fluidization)

• Coating pan: 60–70% (for tablet bed tumbling)

✅ Summary:

• Get equipment gross capacity.

• Apply utilization factor (50–80%) depending on equipment type.

• Multiply by bulk density (for solids) or by output formula (for machines like tablet press).

• Confirm with process validation results.