HEATING EQUIPMENT

HEATING EQUIPMENT HAS POTENTIAL HAZARDS OF HEAT GENERATION AND PROCESS MATERIALS.

FIRE AND EXPLOSION PROBLEMS:

1. PROXIMITY AND COMBUSTIBILITY OF CONTENTS WITHIN THE BUILDING
2. CONSTRUCTION OF BUILDING
3. VENTILATION
4. LOCATION IN THE BUILDING
5. HEAT, GAS, AND SMOKE DISPOSAL.

BOILER FURNACES

USE CONTROLLED COMBUSTION TO GENERATE STEAM TO POWER MACHINERY OR TO PROVIDE HEAT.

THERE ARE 2 TYPES OF BOILERS:

1. WATER TUBE - WATER IS CIRCULATED THROUGH TUBES HEATED BY HOT COMBUSTION GASES AND IS CONVERTED TO STEAM.
2. FIRE TUBE - HEAT COMBUSTION GASES PASS THROUGH TUBES THAT ARE IMMERSED IN CIRCULATING WATER, WHICH IS CONVERTED TO STEAM (SMALL APPLICATIONS).

COMBUSTION RESULTS FROM A CONTINUAL INTRODUCTION OF FUEL AND AIR IN A FLAMMABLE MIXTURE.

• CARBON - HYDROGEN - SULFUR - OXYGEN FROM AIR

OIL, NATURAL GAS, AND PULVERIZED COAL ARE THE MOST COMMON FUELS FOR BOILER FURNACES.  HOWEVER, SOME INDUSTRIES MAY USE LPG, FLAMMABLE LIQUIDS, OR WASTE GASES.

THE FLOW RATE OF FUEL AND AIR, THE FUEL - AIR RATIO, AND THE IGNITION SOURCE MUST BE CONTROLLED.  IF ANY OF THESE FACTORS ARE IMBALANCE, AN EXPLOSION MAY OCCUR.

Examples of Industrial boilers.

HAZARDS

THE PRINCIPLE HAZARDS ARE EXPLOSION AND FIRE CAUSED BY BUILD UP OF COMBUSTIBLE FUEL - AIR MIXTURES.

• EQUIPMENT MALFUNCTION - OPERATOR ERROR - FIRE UP - BLOW DOWN

FIRE PRESSURE VESSELS OPERATE ABOVE 600°F

UNFIRED PRESSURE VESSELS OPERATE BELOW 600°F

• HIGH PRESSURE - ABOVE 15 P.S.I.
• LOW PRESSURE - BELOW 15 P.S.I.

TYPICAL BOILER PROBLEMS INCLUDE:

1. OVERHEATING
2. CRACKING AT THE TUBE ENDS
3. CRACKING AT THE FURNACE ENDS
4. COLLAPSING OF THE FURNACE
5. CRACKING OF THE TUBE SHEETS
6. CRACKING OF THE WELDS

INSPECTION

BOILERS REGULATED UNDER AMERICAN SOCIETY FOR MECHANICAL ENGINEERS (ASME).

• ASME CERTIFIES MANUFACTURER'S ABILITY TO BUILD PRESSURE VESSELS.

INSPECTIONS ARE PERFORMED AS PER ASME BY CERTIFIED INSPECTORS.

• CERTIFICATION THROUGH NATIONAL BOARD OF BOILERS AND PRESSURE VESSEL INSPECTORS.

OVENS AND FURNACES

THERE IS NO CLEAR DISTINCTION BETWEEN OVENS AND FURNACES.

NFPA 86 DIVIDES INTO 4 OPERATING CLASSIFICATIONS:

• CLASS A: ATMOSPHERIC PRESSURE, MAY LEAVE BURNING VOLATILE PARTICLES.
• CLASS B: ATMOSPHERIC PRESSURE, DOES NOT LEAVE BURNING PARTICLES.
• CLASS C: ABOVE 1400°F, ACCOMMODATE SPECIAL ATMOSPHERES (METALLIC HEAT TREATING)
• CLASS D: UNDER VACUUM, CAPABLE OF HIGH TEMPERATURES

CLASSIFICATION BY HANDLING SYSTEM:

• BATCH TYPE:  CONSTANT TEMPERATURE THROUGHOUT, MATERIAL IS PLACED IN PRE-DETERMINED POSITION AND REMAINS THERE UNTIL REMOVED (COOKIES)
• CONTINUOUS TYPE:  MATERIAL MOVES ON CONVEYOR WHILE BEING HEATED AT DIFFERING TEMPERATURES.
• HEAT MATERIALS BY EITHER DIRECT FIRING METHOD OR INDIRECT FIRING METHOD.  PRINCIPLES OF CONDUCTION, CONVECTION AND RADIATION ARE USED.
• INSPECTION
  • ARE THERE ANY FUEL LEAKS?
  • SUFFICIENT INSULATION AND / OR CLEARANCES?
  • ADEQUATE VENTILATION?  REMOVAL OF FLAMMABLE VAPORS.
  • EXPLOSION VENTING.
  • MAINTENANCE PROCEDURES, REVIEW CHECK SHEETS, INSPECTION REPORTS.

       
INDEX HEAT-UTILIZATION EQUIPMENT

FPT 102 - Fire Prevention and Inspection // Instructor: Kevin M. Kolb        Slide #1