Module 1 and 2 a
- 1. MODULE 1 WELDING INSPECTION & CERTIFICATION AWS QC-1-96 Standard for AWS certification of welding inspectors. Inspection decision is based on facts, condition of the welds and acceptance criteria mentioned in specification. Near vision acuity on Jaeger J2 at 12 inch and complete color perception test. Professional attitude, decision must be based on facts, so that it is impartial and consistent. KASH – Knowledge, Attitude, Skills and Habits Drawings, Codes, Standards, and Specifications must be reviewed before starting the job. Pre job review reveals all the hold points for inspection, procedure and welder qualification. 5/184-- Welding Inspector need to have basic knowledge of welding and welding processes, safe works habits and maintain inspection records. Destructive testing and NDE knowledge advantageous. Errors to be single lined cut and corrected, initial and dated. Welding Inspector must be good communicator. Sr. Certified welding Inspector must have 15 years of experience including 6 yrs as Cert. Welding Inspector. (CWI). Good quality is essential for economics, Safety, Govt. Regulations, Global competition, use of less conservative design. The best inspector listens well. 3/184-- Before welding Inspector will check drawings and specifications to ensure specific weld quality requirement and degree of Inspection. Technical Reference-- WI- 80 – Welding Inspection. A1.1- Metric practice guide for welding. A 2.4- Standard symbols for welding and NDE. A3.0 - Standard welding terms and definitions. B1.10- Guide for NDE of welds. ASC Z 49.1- Safety in welding, Brazing, and Cutting. ANSI / AWS- QC 1-96 Standard for AWS Certification of welding inspection. Inspection team consists of Destructive testing specialist, NDE Specialist, Code Inspector, Military or Government Inspector, Owner representative, In-house Inspector. THE BEST WAY TO DEAL WITH PUBLIC STATEMENT IS TO SIMPLY AVOID THEM WHENEVER POSSIBLE. CWI attends the visual inspection of welding. CWI --High school + 5 years experience or 8th class + 10 years, or Less than 8th class + 15 years experience is minimum qualification.. CWI exam shall be in 3 parts. 1. Fundamental closed book exam of 150 multiple choice question. 2. Practical exam of 46 questions. 3. Open book code- 46 Questions. To pass in all parts 72% marks essential in each part. On passing the person is qualified for visual examination of welds. MODULE 2 SAFE PRACTICE FOR WELDING INSPECTORS 11/184-- ANSI/ASC Z 49.1- Safety in Welding, Cutting and Allied processes. Training is mandatory under provisions of OSHA. A fume pume is smoke like cloud containing minute solid particles arising directly from area of melting metal. Fumes are metallic vapors condensed with particulates.
- 2. MSDS provides OSHA permissible exposure limits known as Threshold limit value. TLV. It is a registered trade mark of the American Conference of Governmental and Industrial Hygienists (ACGIH). Training for hazardous material is essential for employees as per OSHA hazard communication standard 29 CFR 1910.1200. Good house keeping is essential to avoid injuries. Area must be clear of tripping hazards. Walls in the welding area should be painted with low reflectivity finish for ultra violet radiation. Paints formulated with Titanium Oxide or Zinc oxide have low reflectivity to ultra violet radiation. Pigments based on powdered or flaked metals reflect ultra violet radiation and hence should not be used. Floor around welding area should be clear of combustible material within 35 ft. radius. 13/184-- Fire watch to be provided near combustible materials. Standards for welding PPEs are specified in ANSI publication Z 87.1 i.e. Practice for Occupational and Educational eye and face protection. During submerged arc welding arc is covered by flux and is not readily visible, however as arc occasionally flashes through flux burdex, operator must wear tinted safety glass. Pant should be worn outside the shoes. Noise control standard General Industrial Standards 29 CFR 1910.95. Air Carbon arc and Plasma arc cutting generates high level of noise. 14/184-- During maintenance of machinery/ Equipment pinch point should be blocked to prevent them from closing in case of equipment failure. Over exposure is that which is hazardous to health or exceeds the permissible limit specified by a regulatory authority—OSHA regulation 29 CFR 1910.1000 covers this topic. Fumes and gases are usually a greater concern in arc welding than in Oxy fuel gas welding- cutting and brazing. The fumes and gases generated during arc welding if likely to cause higher exposure than permissible limit with available ventilation suitable respiratory protection must be used. EXPOSURE FACTOR- Welders must be trained to keep head away from fume pume or to keep on one side of pume. Types of Ventilation- Local ventilation extracts near the welding area locally. General ventilation changes or filters the air in entire area. Close fitting helmets are more effective in reducing exposure. Paint containing lead or plating containing cadmium generate dangerous fumes during welding/ cutting. Galvanized material creates zinc fumes which are harmful. 15/184 VENTILATION.- Fumes generated by/ during welding and cutting consists of small particles which remain suspended in atmosphere for a very long time. Hence fume concentration in a closed area increases over a period of time. Natural, Mechanical or Respiratory ventilation must be provided for all welding and cutting, brazing and related operation. During welding in confined space special care must be taken. Pl refer ANSI publication Z 117.1 Safety requirements for working in tanks and other confined space. Gas cylinder must be located out side the confined space. Welding power should be located out side of confined space to reduce the danger of engine exhaust and electrical shock. Inside lighting must be low voltage 12 V. If 110V the circuit must have ground Fault Circuit Interrupter.(GFCI) A trained helper , stand by at the entry point to confined space must be stationed always. It must be ensured to keep airborne contaminants in breathing atmosphere, netilation also must be provided. (1) Assure adequate Oxygen for life support,( 19.5% by volume) (2) Prevent oxygen reach atmosphere more than 23.5% by volume. (3) Prevent accumulation of flammable mixture. Confined space must not be entered unless well ventilated. Before entry in the confined space gas test must be conducted. Heavier than air gases like CO2, Propane may accumulate in the bottom of pits and low areas near floor. 16/184 Toxic metals- Antimony, Arsenic, Barium, Beryllium, Cadmium, Chromium, Cobalt, Copper, Lead, manganese, Mercury, Nickel, Selenium, Silver, Vanadium Filling one cylinder from other is dangerous and should never be permitted. Cylinder storage area must be – 28 C to 54 degree C. Acetylene and LPG cylinders must be stored in up right position..
- 3. Valve protection cap must be in its position when cylinder is not in use. 17/184 Before connecting the regulator to the cylinder the valve must be opened very little and closed immediately ie CRACKING. All flammable gas cylinders have left hand threads and non flammable cylinders have right hand threads. Fuel gas cylinders of low pressure must not be opened more than one thread for safety reasons. This usually provides adequate flow and allows rapid closure of the valve in case of emergency. High pressure cylinder valves usually opened fully to back seat(seal) packing to prevent leak during use. Cylinders must not be emptied completely. There must be pressure of 25 PSI of contents remaining. This prevents possible contamination by atmosphere during shipping. MANIFLOD It is used when gas is needed without interruption or at higher delivery rate. Piping and fitting for acetylene manifold must not be un alloyed copper or alloy containing more than 70% copper. Those gases react with copper under certain condition to form unstable copper acetylide which can detonate under shock or heat. Manifold must have a over pressure relief valve and each fuel gas cylinder branch line should have a back flow check valve and flash arrestor. Oxygen is non flammable but can initiate combustion and accelerate it.. Pure oxygen supports combustion more vigorously than air. Oxygen must never be used to power air tools. 19/184 Argon, Helium and Nitrogen are used for shielding with some welding processes. All these are used as brazing atmosphere. These gases are colorless and odorless. If any confined space has these gases analysis must be used to check after purging for adequate oxygen in place before entering. Electric Current Shocks greater than 6 mili Ampere are considered primary as they can cause direct body harm. Steady current between 0.5 mA to 6mA are considered SECONDARY SHOCK CURRENTS. These can cause involuntary muscular reaction. Automatic machine controls that safely reduce open circuit voltage are recommended for welding to be done under hazardous conditions. ANSI/ASC Z 49.1 Safety in welding cutting and allied processes. ANSI/NFPA 70 is national electric code for elec. Installations. Actual current is higher than shown by indicator on welding machine if welding is done with short leads or low voltage or both. END