VENTILATION, TEMPERATURE & HUMIDITY Section 23(2)(ii) – OSHWC Code 2020

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1.1 INTRODUCTION

Section 23(2)(ii) mandates that adequate ventilation must be provided in every mine building, workplace and premises to ensure:

• Comfortable temperature
• Adequate air movement
• Acceptable humidity levels
• Removal of impurities, foul smell, dust, fumes, vapours

This requirement applies broadly to all surface and welfare buildings since Draft Rules cover both surface & underground mines under general workplace hygiene provisions.

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1.2 OBJECTIVES OF VENTILATION SYSTEM Ventilation must:

1. Maintain fresh air supply for workers.
2. Prevent heat stress by controlling temperature.
3. Keep humidity at safe levels (40–70% ideal).
4. Dilute and remove:
• Odours
• Bacteria-laden air
• Moisture
• Dust & fumes from processes
5. Ensure thermal comfort for workers.
6. Create hygienic conditions in welfare units.

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1.3 AREAS WHERE VENTILATION IS MANDATORY 

 Section 23(2)(ii) specifically includes all workplace buildings: 

  A. Welfare Buildings

• Canteen
• Rest shelters
• Change rooms
• Bath rooms
• First-Aid rooms
• Ambulance rooms
• Creche rooms

B. Operational Buildings

• Workshops
• Pump houses
• Sub-stations
• Compressor houses
• Stores & godowns

C. Administrative Buildings

• Offices
• Time office
• Control rooms
• Security rooms

D. Special Areas

• Battery charging rooms (fume control)
• Fuel storage sheds
• Explosive storage office area
• Chemical handling area (if any)

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1.4 REQUIREMENTS FOR ADEQUATE VENTILATION 

  1.4.1 Natural Ventilation Must be ensured through:

• Windows
• Doors
• Ventilators
• Louvers
• Roof ventilators
• Air shafts
• Ridge vents

Buildings must be designed to promote cross-ventilation. 

  1.4.2 Mechanical Ventilation Used where natural flow is insufficient. Includes:

• Exhaust fans
• Roof extractors
• Fresh air blowers
• Wall-mounted ventilation units
• HVAC systems for temperature/humidity control

When Mechanical Ventilation is Compulsory:

• Chemical or paint rooms
• Battery charging rooms (H₂ gas hazard)
• Canteen cooking area
• Toilets
• Workshops with welding/fumes
• Enclosed rooms with poor airflow

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1.5 TEMPERATURE CONTROL 

  Acceptable Standards Mine workplace buildings must maintain temperature:

• Comfortable to workers
• As far as practicable not exceeding ambient limits
• Avoiding extreme heat accumulation especially in:
• Workshops
• Compressor rooms
• Canteens
• Rest shelters
• First-aid rooms

Controls include:

• Proper ventilation
• Insulated roofing
• Heat-resistant paint
• Sunshade & green belt
• Air circulators/fans
• Air cooling systems (where necessary)

Why temperature control is necessary? Because high temperature can cause:

• Heat exhaustion
• Heat cramps
• Dehydration
• Loss of concentration
• Reduced productivity
• Increased accident probability

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1.6 HUMIDITY CONTROL 

 High humidity causes:

• Sweating & discomfort
• Heat stress
• Mold/microbial growth
• Slippery floors
• Corrosion of equipment

Humidity can be controlled through:

• Adequate ventilation
• Dehumidifiers (if required)
• Drainage systems to prevent dampness
• Insulation to reduce condensation
• Drying fans in bath/change rooms

Ideal humidity: 40%–70%.

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1.7 REMOVAL OF HARMFUL IMPURITIES Ventilation must eliminate: 

  1. Odours From:

• Toilets
• Canteen
• Garbage areas

2. Bacteria & Micro-organisms Good ventilation reduces disease transmission. 

  3. Fumes & Vapours From:

• Welding
• Painting
• Cleaning chemicals
• Battery charging

4. Dust particles Especially in store/workshop. 

  5. Heat & Moisture From cooking, bathing, and industrial processes.

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1.8 SPECIAL VENTILATION REQUIREMENTS IN MINING BUILDINGS 

  A. Toilets

• Exhaust fan mandatory
• No foul smell
• Continuous air circulation

B. Bath/Change Rooms

• Moisture removal essential
• Non-stagnant humid air

C. Canteen

• Separate ventilation for cooking area
• Exhaust hoods
• No smoke/odour accumulation

D. Workshop

• Exhaust to remove fumes & heat
• Roof ventilators for natural upward flow

E. Compressor & Sub-station Rooms

• Good airflow to prevent:
• Heat accumulation
• Equipment overheating

F. First-Aid & Ambulance Rooms

• Comfortable temperature
• Proper ventilation for hygiene

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1.9 VENTILATION DESIGN PRINCIPLES (EXAM FAVOURITE)

1. Cross Ventilation – fresh air enters one side & exits opposite side.
2. Stack Effect – hot air rises & exits through roof vents.
3. Wind-Driven Ventilation – wind scoops & ridge ventilators.
4. Mechanical Extraction – exhaust fans pulling air out.
5. Mechanical Blowing – introducing fresh air into room.
6. Airflow Uniformity – avoiding dead zones.

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1.10 INSPECTION & MAINTENANCE Inspection Frequency

• Daily (toilets, canteen, enclosed areas)
• Weekly (workshops, store, rest shelters)
• Monthly (ventilator cleaning, fan inspection)

Inspection Parameters

• Fan working condition
• No blockage of vents
• Clean air pathways
• No stagnant humid air
• Temperature not excessive
• Odour-free environment

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1.11 CONSEQUENCES OF POOR VENTILATION

• Heat stress
• Fainting
• Mold formation
• Respiratory irritation
• Bad odour & poor hygiene
• Increased infection risk
• Reduced morale & productivity
• Violation of OSHWC Code → penalties

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2. QUICK ONE-LINERS (REVISION – 30 POINTS)

1. Ventilation required under Section 23(2)(ii).
2. Objective: maintain fresh, clean air.
3. Controls: natural + mechanical ventilation.
4. Remove odours, fumes, heat, humidity.
5. Adequate ventilation needed in all mine buildings.
6. Toilets must have exhaust fans.
7. Canteens require fume extraction.
8. Workshops need roof ventilators.
9. Battery rooms need forced ventilation.
10. Temperature must remain comfortable.
11. Ideal humidity 40–70%.
12. Prevent heat stress & discomfort.
13. Ventilation reduces infection risk.
14. Good airflow prevents corrosion.
15. No stagnant air pockets.
16. Ventilation must dilute pollutants.
17. Essential for hygiene facilities.
18. Must meet DGMS safety expectations.
19. Ventilation must be inspected regularly.
20. Exhaust fans must be functional.
21. Sub-stations require good airflow.
22. Airflow prevents condensation.
23. Hot air must exit from top vents.
24. Ventilation improves worker morale.
25. Drains must not cause humidity.
26. Fans must be maintained.
27. No stale air in welfare buildings.
28. Air quality directly affects productivity.
29. Manager responsible for compliance.
30. Proper ventilation prevents accidents.

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3. DESCRIPTIVE MODEL ANSWER 

Question:
Explain in detail the requirements of Ventilation, Temperature & Humidity under Section 23(2)(ii) of the Mine Workers Rules, OSHWC Code 2020. Model Answer:
Section 23(2)(ii) of the Draft Mine Workers Rules requires that every mine building and workplace must be provided with adequate ventilation to ensure comfortable temperature, acceptable humidity, and a continuous supply of fresh air. The purpose of this provision is to maintain hygienic and safe working conditions by preventing the accumulation of heat, moisture, odours, dust, fumes, and harmful vapours. All categories of mine buildings, including welfare structures like toilets, change rooms, canteens, first-aid rooms, ambulance rooms, operational buildings such as workshops, pump houses, substations, and administrative offices must have proper natural or mechanical ventilation. This includes the use of windows, louvers, ventilators, exhaust fans, roof extractors and mechanical blowers wherever natural ventilation is insufficient. Temperature in these premises must be maintained at a level comfortable to workers, preventing heat stress and fatigue. Similarly, humidity must be controlled to avoid dampness, microbial growth, and discomfort. Bath rooms, toilets, canteens, and enclosed workshops require special ventilation arrangements. The employer must conduct regular inspection and maintenance of ventilation systems to ensure they function effectively. The overall objective of Section 23(2)(ii) is to safeguard worker health and improve workplace comfort, thereby promoting safety, hygiene, and productivity in mines.

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