This document provides information on various hot work activities and safety precautions. It discusses natural gas, welding, gas cutting, grinding, commissioning, and hot tapping. For each topic, it defines key terms, describes the process, and lists associated hazards and control measures. The key points are: natural gas is flammable and odorless, welding involves heating metals to join them, gas cutting uses fuel gases and oxygen to cut metals, grinding uses abrasive wheels to remove material, and hot tapping connects to pressurized pipes and vessels without shutting them down. Safety precautions include permits, inspections, PPE, ventilation, fire watches, and eliminating ignition sources and combustibles from work areas.

1. 1
Hot Work Safety

2. What is Natural gas ?
• Naturally occurring mixture of Hydrocarbons & Non-Hydrocarbons found in
porous formation beneath the earth surface often in association with crude
petroleum Mixture of C1 to C7 hydrocarbons, Mainly CH4 (Methane) Environment
friendly fuel (Contains no lead / very less Sulphur)
• At atmospheric pressure and temperature, natural gas is lighter than air. The
density (at 20º) C of Air =1.2 kg/m3 Natural gas = 0.65 kg/m3 LPG = 1.8 kg/m3
• Very good combustion properties - suitable for various applications.
• Natural gas is colorless, tasteless and non-toxic (but Asphyxiate) .Natural gas
has no odor of its own, it is odorless.
However, it is highly flammable.

3. Natural Gas Flammability Limits
Combustibility in Air
Percent by Volume
Mixture too rich
to support
combustion.
Combustible
Range
Mixture too lean
to support
combustion.
0%
5%
15%
100%
Flammability / Explosive Limits & Ranges
Natural Gas LPG Petrol Vapour
5 – 15 % 1.8 – 10 % 1.3 – 7.4 %
LEL : The minimum
concentration
of flammable gas in air above
which it can be ignited
UEL : The maximum concentration
of flammable gas in air, below which
it can be ignited

4. What is Hot work ?
• Hot work is any work process in which a flame is used, or sparks or other sources
of ignition may be produced, including:
• open flames e.g., cutting, welding, burning.
• electrical, friction or impact sparks e.g., air gouging, riveting, drilling, grinding,
chipping
• sparks resulting from the discharge of static electricity
• Hot surfaces such as engine manifolds and exhaust systems, brakes, hot
bearings, welding or cutting torches, coils and resistors
• heated gases
• Internal combustion engines.
• Hot Work. Any work involving welding, brazing, soldering, heat treating, grinding,
powder-actuated tools, hot riveting and all other similar applications producing a
spark, flame, or heat, or similar operations that are capable of initiating fires or
explosions.

5. TYPE OF HOT WORK :
 Welding
 Gas Cutting.
 Grinding
 Commissioning .
 Hot Tapping.

6. What is welding?
Welding is a process, in which two parts of the same or different metals are joined by causing the
edges to melt and unite while molten without the aid of hammer or compression. When cool, the
parts form one piece of metal
Welding

7. Welding Process:
Diversity of welding processes
Welding
Solid state welding
Soldering and brazing
Fusion welding
Electrical energy
Chemical energy
Other processes
Non consumable
electrode
Consumable
electrode
Resistance welding
Cold welding
Friction welding
Diffusion welding
Flash welding
Ultrasonic welding
Explosion welding
Gas metal arc welding
Shielded metal arc
welding
Submerged arc welding
Flux cored arc welding
Electrogas welding
Electroslag welding
Gas tungsten arc
welding
Atomic hydrogen
welding
Plasma arc welding
Oxyacetylene welding
Oxyfuel gas welding
Laser beam welding
Thermit welding
Electron beam welding
Soldering
Brazing

8. General safety precaution
 Double earth should be provided to welding M/c.
 Terminals of the welding cables should be provided with lugs and kept tight.
 Joints in the cables should be made with terminals, kept tight and well insulated with heat resistant tape
 Cable should be free from joints at least for a length of three meters from electrode holder to avoid shock hazards.
 Other electrical cables, gas cutting hoses, should not be laid with welding cables to avoid insulation damage, fire
 For the return lead use only proper cables. use of reinforcement steel, structural steel members should be avoided.
 Body earthing should be provided to portable ovens
 Proper eye protection should be used by helper to protect against radiation hazards-ARC EYE .
 Fixing return lead on bottom of structural steel structures and welding at elevation should be strictly
provided.
 Welding machine should be kept within the visibility of the welders.
 Never change electrode with bare hands or wet gloves.
 Provide proper working platform for welders to work at height.
 Welding bits should not be allowed to drop from height. provide suitable box to keep the hot welding bits and should
be lowered down on daily basis.

9. General Safety Precautions:
 Molten slag should be not allowed to fall. use suitable protections like fire
blanket/G.I Sheet etc to arrest the falling slag
 Fire extinguishers should be kept near welding spot and keep a fire watch .
 Remove combustible materials from the vicinity before undertaking welding
job
 When electrode holders are to be left unattended, the electrodes shall be
removed, and the holders shall be so placed or protected that they cannot
make electrical contact with employees and conducting objects.
 Use separation barrier screen for multiple work at same location to protect the
person nearby
 Ventilate the work area properly
 Make sure there are no coated surface within 4 inches of the weld area

10. Welding work inspection
 Wear personal protective equipment appropriate to the specific task
 Inspect the work area. Ensure that sparks or molten metal will not contact flammable or combustible
materials
 Be sure that all welding leads and hose are off floors, walkways and stairways
 Never perform welding cutting or burning barrels, tanks pipes or other vessels that may have
contained combustible or unknown materials without clearance of safety department
 Barricading ,blanketing, shielding and placing of spark tray to contain spark and hot sludge
 Parts and accessories of welding equipment that will be inspected are:
•Grounding/ Earthing of equipment body.
•Earth leakage circuit breaker.
•Electrical and welding cables.
•Electrode holder

11. PPE
• Wear correct clothing to protect from UV radiation, hot metal, sparks and slag
• Keep clothing clean of oil and grease
• Welding gloves
• Do not wear rings or jewelry
• Do not wear synthetic clothing, this fabric can burn/melt

12. Hazards and Risk
Hazards Control Measures Example
Welding Arc flash
Dehydration / heat stress
Specific PPEs for welders
• flame-retardant coveralls
• fire-resistant gauntlet gloves
• Safety shoes.
• Welding shield with UV Filter Glass.
• flame proof screens to avoid arc flash to
the persons in the vicinity
• Adequate drinking water facility, frequent
work intervals, rest shed and ventilation
arrangements shall be provided.
Pipe fit up and Welding

13. Hazards and Risk
Hazards Control Measures Example
Electrical hazards
Improper electrical wiring
Poor housekeeping of electrical
cables
No provision of grounding
Wet spaces, Humid environment
→ decreased electrical resistance
• Welding shall be avoided at waterlogged
areas & heavy rain period
• Stay on insulation mat, dry wooden
board or non-conductive stand
• Earth resistance of all equipment, DB
and other electrical connectivity or
sources shall be maintained below 1
ohm.
• Power supply shall be tapped from IP 55
/ 65 distribution board
• Qualified Electrician as per IE Rules (ITI
with Electrician license from respective
state Electrical Licensing Board) is only
authorized for electrical installation.
Pipe fit up and Welding

14. Hazards and Risk
Hazards Control Measures Example
Ergonomics
• work in one position for long
periods of time cause
Musculoskeletal disorder
• Limited workspace
• Provide standard working platform for
working at height for pipe welding
• minimum 700mm working space shall be
provided for welders in the trench.
• Job rotation for welders.
Pipe fit up and Welding

15. Hazards and Risk
Hazards Control Measures Example
Fire and Explosion hazards
The intense heat and sparks
produced by welding can cause
fires or explosions if combustible
or flammable materials are in the
area.
• Inspect welding area before starting
• Remove combustible, explosives and
flammable materials prior to welding,
• Obtain Hot work permit
• deployment a fire watch person
• Place a fire extinguisher
• Use lugs and double insulated cables.
• welding power sources should be located
in a secure position outside of the
confined space
Pipe fit up and Welding

16. Hazards and Risk
Hazards Control Measures Example
Confined Space Hazard
Oxygen enrichment
Entering into Pipe for coating or
welding work considering as
Confined space.
• Confined space Permit must be
completed if enter into Pipe.
• Oxygen level shall be maintained
between 19.5 % to 23.5% is the
acceptable oxygen level for work without
an air supplied respirator.
• Detect explosive limits and presents of
acceptable toxic gas limits using multi
gas detector at frequent intervals as per
confined space work permit.
• Install local exhaust ventilation system as
per the workspace requirements
• Attendant shall be positioned to monitor
entry and exits of confined space
Pipe fit up and Welding

17. Hazards and Risk
Hazards Control Measures Example
Engulfment
when there is a potential for a
person entering the space to be
engulfed or trapped by liquid or a
fine flow able solid such as sand
In order to mitigate the engulfment hazard,
• Close the valves to stop the flow and
ensure drained before entry.
• Implement LOTO – Lock out and Tag out
Procedure.
• Confined space permit and procedure
shall be implemented.
• Pipes dia of 700mm and below is banned
from entry
• LOTO Procedure
• Prior Inspection in the
Confined space.
Pipe fit up and Welding

18. Procedure for the Safe execution of Work activities:
A Permit to Work for
Hot Work(HSE 101).
Site Specific Risk
Assessment(SSRA).
Hazard Identification
and Risk
Assessment(HIRA).
Job Safety
Analysis(JSA).
Toolbox Talk Before
the start of work
activities.
Inspect & Check the
surrounding area
Remove all
combustible
materials
Inspect and check
welding equipment
and its accessories.
Electrical parts will
only be repaired and
serviced by
qualified electrical
worker.

19. Gas cutting
“Cutting refers to operation involving the used of compressed oxygen-acetylene/LPG gas torch”.
Something to think on……
Every time you use the oxy-acetylene equipment, if certain safety guidelines are not followed, it would be
the same as handling live explosives ready to go off…….

20. What is Oxygen
• Remember, oxygen is not air;
• There is approximately 21% oxygen in normal air;
• Oxygen is found naturally in the atmosphere;
• It is produced industrially by distilling air below it’s freezing point;
• Pure oxygen does not burn or explode;
• Oxygen is an “accelerant” , it causes every thing it meets to burn hotter and faster;
• Air has a vapor density of 1.000, Oxygen is heavier than air (1.105) This means if an
oxygen bottle is leaking, the gas will settle in low areas before diffusing back into the
atmosphere;
• 30% oxygen in the atmosphere will cause things to burn or explode 8 times faster

21. What is acetylene
• Acetylene is a compound of Carbon and Hydrogen (C2H2) a member of the
hydrocarbon gases;
• Explosive range is 3.0 to 93%;
• Needs only 10% of oxygen to ignite;
• Produced when calcium carbide is mixed with water;
• It is an unstable gas, will violently decompose when in a pure state above 15 psi;
• Has a burning temperature of 4,600o F, 5,700o F when burned with oxygen;
• Auto-ignition temperature is 7630o - 824o F, this means if acetylene reaches 30 psi
in a free state, it can explode by itself without a spark or flame being present;
• Remember, acetylene is a very dangerous gas.

22. Gas Regulators
Low pressure
gauge
Indicates the
delivery
pressure to the
hoses & torch
High pressure gauge
Indicates the pressure
from tank
The Inlet Connections
Oxygen are right-handed
thread / Acetylene are left-
handed thread
Keep free of oil, grease, &
dirt
The Pressure adjusting screw
Turning clockwise allows the gas allows to flow
Turning counterclockwise reduces or stops the
gas flow

23. Some more info on regulators
Warning - Always keep the regulator free of oil, grease and other flammable substances
Never use oil or grease on the regulator, cylinder or manifold connection
DO NOT change the inlet connection on a regulator in an attempt to use the regulator for a different gas
service
Never stand in front or behind a regulator when opening the cylinder valve

24. Backfires and Flashbacks
• Backfires occur when the torch flame burns back into the torch tip and is extinguished with a
loud pop.
• They occur either because the torch tip touched the work or because of insufficient gas
pressure.
• They are generally harmless. However, flashbacks are more serious when the flame front
does not extinguish, but burns back sometimes beyond the mixing chamber, through the
hoses, and even into regulator and supply.
Flashback arrestors:
• Flashback arrestors are designed to prevent a flashback from reaching upstream equipment.
• They offer added safety and often include reverse flow check valves in a single unit.

25. Grinding:
Grinding is a material removal process accomplished by abrasive particles that are contained in a bonded
grinding wheel rotating at very high surface speeds.
The rotating grinding wheel consists of many cutting teeth ( abrasive particles ) and the work is fed relative
to the rotating grinding wheel to accomplish material removal.
SPECIFICATION OF GRINDING WHEELS/CUTTING WHEEL:
•Standard wheel markings
•Diameter of the wheel
•Bore diameter of the wheel
•Thickness of the wheel
•Type of the wheel
• AG5 – 5 inches wheel
• AG7 – 7 inches wheel
• AG9 – 9 inches wheel
Commonly used machines:

26. What is a Grinding Wheel?
• MULTIPOINT Cutting tool comprising of selectively sized ABRASIVE GRAINS, held
together by means of a BONDING MATERIAL called BOND with suitable SPACING of
grains in between.
Cause of Breakage of Grinding wheel:
• Never mount a damaged grinding wheel.
• Don’t grind material for which the wheel is not designed.
• Never mount a grinding wheel on a machine not designed and guarded for that grinding wheel.
• Never over speed a grinding wheel.
• Failure to properly maintain a grinding machine can cause grinding wheel breakages resulting
in serious injury or death.
• Improper mounting of grinding wheels.
• If you do not know how to use a grinding wheel or the grinder, get help!
• Jamming the work into the grinding wheel.
• Force grinding, so that the motor slows noticeably, or the work gets hot.
• Grinding on the wrong surface of a grinding wheel, i.e., grinding on the side of a Type 1 or
straight grinding wheel.

27. General Safety Precautions:
Storage:
• Grinding wheels shall be stored in such a manner that mechanical damage is avoided and that
they are not subjected to damaging environment.
• Store in dry, frost free conditions in special racks or containers. Store in moderate and constant
temperature.
• Use the wheels held in stock longest first.
Ring Test:
• Cracked wheels can be identified by doing ring test.
• To perform the ring test, wheels should be tapped gently with a light non-metallic implement,
such as the handle of a screwdriver for light wheels, or a wooden mallet for heavier wheels.
• Clear Ringing sound indicates the wheel is free from cracks.
• Dead sound indicates presence of cracks. Such wheels should not be mounted on the machines.
Wheel Guard:
• Before starting the cutting-off or grinding operation, the wheel guard must be in position and
fixed securely.

28. Safety Precautions:

29. Safety Precautions during Grinding/Cutting:

30. Commissioning:
• Commissioning Of Secondary Network.
• Domestic Network Commissioning.
• Commercial Commissioning.
• Steel Pipeline Commissioning.
• Commissioning of different part of the CNG
Station.

31. Hot Tapping:
• Hot tapping, also known as pressure tapping, is a method of connecting (either by drilling or cutting)
to a pressurized system, such as a pipeline or pressure vessel, without removing the pipe or tank from
service.
• Hot Tapping is as per the OCP 20 of the STEEL Pipeline Hot tapping.
Procedure Step:
• Identification of the proper location for tapping ensure the minimum Pipe Top Cover of 1.5 Meter and
Horizontal Position.
• Need to take work permit for the all-site work activity.
• Need to ensure the PPE’s and measuring Instruments at the site for the site work Activities.
• Ensure the Fire tender in stand By Condition.
• The roles and Responsibilities shall be clear in case of Any Emergency. Need To take care all the
emergency before the start of emergency.
• Ensure the availability of Competent person near the Isolation Valve with communication System.
• Ensure electrical Isolation of pipeline (TR units shall be switched off).
• Ensure tapping and Fitting (Valves and Welldoer) ready before the hot tapping.

32. Need to Taken care following Operating Parameters :
• Pipe Size.
• Tapping Size.
• Pipeline Operating Procedure.
• Wall Thickness of the Pipeline.
• Pipeline Material Grade.
• Confirm the operating Flow which is match with the requirement or Not.
• Pipeline gas Temperature.
Other Precautionary Measures:
• Area need to be inspected before the start of work activities.
• Pipeline surface shall Ultrasonically Determine the actual wall thickness and freedom from lamination. So
that the visible defects and Wall Thickness must be determined.
• Need to ensure the work environment shall free from any explosive or toxic Vapor before the start of
welding fitting with Pipe.
• Clean the Pipeline area must be inspected.
• Necessary Precautions need to be ensured for the parent metal during Cleaning.
• Need to take all the control Measures as per the OCP 20 for the commissioning of Steel Pipeline.
• Competent workforce need to be deployment of the all-work activities. Conduct Leak Test of Valve with
Nitrogen Purging,

33. Hot Tapping:
• Lower Hot Tapping Machine safely in pit using suitable lifting machinery & scaffolding.
• Ensure proper installation of Hot Tapping Machine with Tapping Valve.
• Ensure tightening of bolts of Tapping Machine, install bleeder valve. Check bleeder valve for
operation & free from any obstruction.
• Nitrogen lock pressure test shall be done for hot tap valve, packing, seal, gasket & bolts. Arrest
leakage if any.
• Ensure following measurement of Fitted Hot tapping Machine
a) Measure distance from the pilot tip to the face of the adapter (Measurement A)
b) Measure distance from top of the valve to the top of the pipe wall (Measurement B)
c) Refer to the manual for the approximate distance the pilot and the cutter must travel to complete
the tap after the pilot contacts the pipe wall (Measurement C)
d) Ensure that pilot is inside the adapter, total of A+B equals the distance the pilot must travel to
contact the pipe. If the pilot tip extends beyond the face of the adapter, total of BA equals the
distance the pilot must travel to contact the pipe wall.
e) Measure the distance the pilot tip extends beyond the cutter teeth. A+B+C (or B-A-C) equals the
total travel distance. Record all the dimensions on the data sheet.

34. Other Safety Precautions:
• Hot tapping operation shall be commenced after ensuring adequate flow
• Tapping valve shall only be closed after ensuring complete tapping & retraction of boring bar.
• Bleeder valve shall be opened for venting the entrapped gas after valve.
• Tapping machine shall be removed after complete achieving "0" pressure.
• Apply blind flange to the tapping, remove valve handle.
• Adequate cordoning & security shall be provided till the110%completion of chamber construction.
• Pipeline Temperature checks at the welding spot to be recorded at regular intervals
Records To be Maintained:
CONSTRUCTION REPORTS
➤ Trenching Report
➤ As Built Drawing or Line Diagram (Isolation valve drawings)
➤ Valid permissions for excavation
TEST CERTIFICATE
➤Welder Qualification test certificate
➤ Fittings Valves
➤Flanges, Gaskets & Fasteners Electrode testing report
➤ Pneumatic Test report of valve
➤ Calibration report of Instrument for Testing

35. General Safety Tips
Appropriate gloves
Clothing free of grease & oil.
Clean work area
Proper Task Training
Fire extinguisher
Proper Eye protection.
Never allow oxygen to contact oil, grease or other flammable substances
Never mix brands
Purge the lines before and after usage
Always wear protective clothing
Use proper eye protection

36. HAZARD
IDENTIFACATION AND
RISK
ASSESSMENT(HIRA)

37. Fire and Explosion Hazards:
• Intense heat and sparks can cause fires or explosions if in the vicinity of combustible or
flammable materials
• Welding and cutting should only be performed in areas free of combustible materials such as
trash, wood, paper, textiles, plastics, chemicals, and flammable dusts, liquids and gases
• Never weld or cut on containers that have held a flammable or combustible material unless
the container is thoroughly cleaned or filled with an inert gas
• A fire inspection should be performed prior to leaving a work area and for at least 30 minutes after the
operation is completed
• Fire extinguishers should be nearby, of proper size, type and number for the hazards involved

38. Health hazards:
 Gases and Fumes…
 Welding “Smoke” is a mixture of very fine particles called fumes and gases
 Welding “Smoke” contains fumes and gases including…
Chromium, nickel, arsenic, asbestos, manganese, silica, beryllium, cadmium,
nitrogen oxides, phosgene, acrolein, fluorine compounds, carbon monoxide,
cobalt, copper, lead, ozone, selenium, and zinc
Generally, gases and fumes come from…
• Base material & filler material
• Coatings & paints
• Shielding gases & chemical reactions
• Process & consumables used
• Contaminants in the air

39. Hazards:
 Short-term effects: Exposure to welding “smoke” may have Effects happen at or very soon after
exposure.
 Long-term effects: Effects may happen after repeated overexposures or an extended time after the
exposure.
•Exposure to zinc, magnesium, copper and copper oxide can cause metal fume fever
• Symptoms of metal fume fever may occur 4 to 12 hours after exposure
• Symptoms include…
• Chills, thirst, fever, muscle ache, chest soreness, coughing, wheezing, fatigue, nausea, and metallic
taste in mouth
Short-term exposures:
Long-term exposures:
• Studies of welders, flame cutters, and burners have shown that welders have an increased risk of lung
cancer and possibly cancer of the larynx and urinary tract
• Remember… welding “smoke” can include cancer causing agents such as…cadmium, nickel, beryllium,
chromium, and arsenic. Welders may experience a variety of chronic respiratory problems, including
(Bronchitis, asthma, pneumonia, emphysema, pneumoconiosis, decreased lung capacity, silicosis, and
siderosis)

40. THANK YOU!
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