Welding and cutting

Welding and cutting

OSHA Outreach Safety Training General Industry Safety Standards

Welding, Cutting, and Brazing

عطقلاو ماحللا لامعأ

Welding Health Hazards

اذكهمو لوزتو ةعاس

ةردقم ىلع رثؤي ضرم وهمو

ببسي نأ نكمملا نمو نيجيسكولا صاصتمل نيتئرلا

نيتيلكلا فلت ىف

Types of Weldingماحللا عاونأ

• Gas Welding (oxy-acetylene gas)زاغلا

• Arc Welding (SMAW – Shield Metal Arc Welding) – (MIG – Metal Inert Gas) – (TIG – Tungsten Inert Gas)

• Oxygen and Arc Cutting

29 CFR 1910.252 General Requirements

ةماعلا تابلطتملا

•

ماحللا ناكم برق نم لاعتشلل ةلباقلا داوملا عيمج داعبإ

نع لقت ل ةفاسمب 35

) مدق 11

.رياطتملا ررشلا ةجيتن ثدحت دق ةئيطب

Welding or Cutting Containers ليماربلاو تايواحلا ىف عطقلاو ماحللا

Filter Lens Shade Number Guide

Welding Operation Shade Number

Shield Metal Arc Welding up to 4 mm electrode 10

Shield Metal Arc Welding (4.8 to 6.4 mm) electrodes 12

Shield Metal Arc Welding (6.4 mm) electrode 14

Gas Metal Arc Welding (Nonferrous) 11

Gas Metal Arc Welding (ferrous) 12 Gas Tungsten Arc Welding 12 Carbon Arc Welding 10 – 14 Torch Soldering 2 Torch Brazing 3 or 4 Light cutting up to 25 mm 3 or 4 Medium cutting 25 to 150 mm 4 or 5 Heavy cutting over 150 mm 5 or 6 Gas welding (light) up to 3.2 4 or 5 Gas welding (medium) 3.2 to 12.7 5 or 6

Gas welding (heavy) over 12.7 6 or 8

Health Protection and Ventilation

ةيحصلا ةياقولاو ةيوهتلا

•

لدعمو ، ماحللا ناكمل ةيكيناكيم ةيوهت ريفوت ةرورض

نع لقي ل ةيوهتلا2000

) بعكم مدق 284

فرغلا ىفو (بعكم رتم

نع اهعافترإ لقي ىتلا16

) مدق 5

.(رتم

•

متي ىرخأ ةشرو لخاد ماحللا ةشرو دوجو ةلاح ىف

كرت متي نأ ىلع زجاح بيكرت2

لفسأ نم غارف مدق

.ةيوهتلا ةلوهسل

Movable Hoods

ةيعضوملا ةيوهتلا

•

متي ةكرحتم ةيعضوم ةيوهت ناكم نم برقلاب اهعضو ةراضلا ةرخبلا طفشل ماحللا

29 CFR 1910.253 Gas Welding and Cutting

زاغلاب عطقلاو ماحللا

• An oxyacetylene welding outfits is basically made up

of: cylinders of oxygen and acetylene, regulators,

hoses, and a torch.

• Oxygen and Acetylene are stored in separate

cylinders in a high pressure, which is controlled by the regulators.

• Hoses carry the gases from the cylinders to the torch

The green hose carries Oxygen The red Hose carries Acetylene.

• The gases are mixed inside the torch When burned

they produce a very hot flame The flame is

regulated by interchangeable torch tips and by the torch valves

Flash Back Arrestor

on the acetylene and oxygen regulators

Non-return Valves on the Torch

General Requirements

• Under no condition shall acetylene

be generated or utilized at a

pressure in excess of 15 psig.

• Using acetylene at a pressure in

excess of 15 psig is a hazardous

practice Free gaseous acetylene is

potentially unstable at pressure

above 15 psig and could

decompose with explosive

violence.

• The decomposition characteristics of

acetylene gas are avoided by keeping the gas in liquid solution and storing

Acetylene

Cylinders are filled with Calcium

Silicate

• When absorbed in this filler, the acetylene

is divided into such small units that, should acetylene decomposition take place in one pore, the heat released is not enough to raise the temperature of the acetylene in the

surrounding pores

• Acetylene is usually supplied in cylinders which have the capacity of up to 300 cubic feet of dissolved gas under pressure of 250 psig at 70º F

• Cylinders shall be kept far enough away

from the actual welding or cutting operation

so that sparks hot slag, or flame will not

reach them When this is impractical shields shall be provided

• Cylinders containing Oxygen or Acetylene

or any fuel gas shall not be taken into

• Cracking: Before a regulator valve is

connected, the valve shall be opened

slightly and closed immediately To clear

the valve of dust or dirt

• The person cracking the valve shall stand to one side of the outlet, not in front of it

• Fuel gas cylinder valves shall be opened 1.5 turns and the wrench shall be left in

position on the stem of the valve

Safety Precautions

Check with a leak

Never expose the acetylene cylinder to strong heat

A burning torch must not be hung on the regulator or expose the cylinder

Cylinders and Containers

• Compressed gas cylinders shall be legibly marked, for the purpose of identifying the gas content.(stenciling – stamping)

• Cylinders should be stored away from

elevators, stairs, or gangways, or other areas where they might be knocked over or

damaged by passing or falling objects

• Where the cylinder is designed to accept a cap, shall always be in place, hand-tight,

except when cylinders are in use or

connected for use The valve protection cap

is designed to take the blow in case of

cylinder falls

• Acetylene cylinders shall be stored valve

end up

Oxygen Cylinders

• Or by a combustible barrier at least 5 feet (1.5m) high having a fire

non-resistance rating

of at least 1/2 hour.

Hot Tapping Basic Procedure

1 Install fitting and valve to the existing

pipeline.

2 Install Hot Tap Machine

3 Perform hot tap through the open valve A

special device retains the “coupon” removed during the hot tap operation.

4 Retract cutter assembly

5 Close hot tapping valve

6 Remove hot tap machine to allow for

connection to new pipe.