Part 3: Pipefitting Fundamentals (Facts 101–150)
Part 4: Welding Knowledge (Facts 151–200)
A refinery cannot operate without properly installed piping systems and high-quality welds. Every gallon of fuel, every pound of steam, every cubic foot of natural gas, and every process chemical depends on thousands of pipefitters and welders doing their jobs correctly.
This section covers practical knowledge that every refinery journeyman should understand.
PART 3 – PIPEFITTING FUNDAMENTALS (Facts 101–150)
101.
Pipefitters install systems that carry liquids, gases, steam, chemicals, and process fluids.
102.
No two piping systems are exactly alike.
103.
Blueprints show where systems go, but field conditions often require adjustments.
104.
Pipe is identified by nominal pipe size (NPS), not its exact outside diameter.
105.
Pipe Schedule refers to wall thickness, not pressure rating.
106.
Schedule 40 is one of the most common pipe schedules used in industry.
107.
Schedule 80 has a thicker wall than Schedule 40.
108.
Stainless steel pipe has different dimensions than copper tubing.
109.
Pipefitters spend as much time measuring as installing.
110.
A small measuring mistake can multiply throughout an entire piping system.
111.
Proper fit-up makes welding faster and produces better results.
112.
Pipe strain should never be forced into equipment nozzles.
113.
Thermal expansion must always be considered during installation.
114.
Expansion loops reduce stress on piping systems.
115.
Pipe supports control movement and vibration.
116.
Improper supports can cause premature equipment failure.
117.
Pipe hangers must allow designed movement where required.
118.
Spring hangers compensate for vertical movement.
119.
Anchor points prevent unwanted pipe movement.
120.
Guides keep expansion moving in the intended direction.
121.
Flanges must match pressure class and facing type.
122.
Raised-face and ring-type joint (RTJ) flanges are not interchangeable.
123.
Proper gasket selection is critical for leak-free service.
124.
Bolts should be tightened using the proper sequence.
125.
Uneven bolt loading can damage flanges.
126.
Pipefitters regularly calculate offsets.
127.
Rolling offsets require three-dimensional thinking.
128.
Field fabrication saves time during installation.
129.
Prefabrication reduces work performed inside operating units.
130.
Pipe spools are often fabricated before arriving at the jobsite.
131.
Isometric drawings provide fabrication dimensions.
132.
Pipefitters often verify dimensions in the field before cutting material.
133.
Cold spring may be used to reduce thermal stress.
134.
Every valve has a preferred installation orientation.
135.
Valve accessibility is part of good piping design.
136.
Dead legs should be minimized where possible.
137.
Steam systems require proper drainage.
138.
Steam traps remove condensate from steam lines.
139.
Improper steam trap operation wastes energy.
140.
High-energy piping requires additional inspection.
141.
Pipefitters frequently work with carbon steel.
142.
Stainless steel requires additional cleanliness during fabrication.
143.
Copper tubing is common in instrument and utility systems.
144.
Victaulic grooved piping speeds installation.
145.
Threaded piping is generally limited to smaller pipe sizes.
146.
Socket-weld fittings are common on smaller high-pressure systems.
147.
Butt-weld fittings provide smooth flow characteristics.
148.
The best pipefitters think several steps ahead before making the first cut.
149.
Good craftsmanship is measured in thousandths of an inch—not by luck.
150.
An experienced pipefitter understands that precision today prevents problems for decades.
PART 4 – WELDING KNOWLEDGE (Facts 151–200)
151.
Every refinery relies on thousands of structural and piping welds.
152.
A weld is only as strong as its preparation.
153.
Joint cleanliness directly affects weld quality.
154.
Proper bevel angle allows complete penetration.
155.
Root opening influences weld penetration.
156.
Poor fit-up creates unnecessary welding problems.
157.
Heat input affects the finished weld.
158.
Excessive heat can distort piping.
159.
Insufficient heat may lead to lack of fusion.
160.
Every welding process has strengths and limitations.
161.
SMAW (Stick) remains one of the most common refinery welding processes.
162.
GTAW (TIG) produces extremely clean welds.
163.
GMAW (MIG) offers high production rates in fabrication shops.
164.
FCAW is widely used for heavy structural work.
165.
Submerged Arc Welding is common for large shop fabrication.
166.
Orbital welding is often used for high-purity piping systems.
167.
Pipe welding usually requires multiple passes.
168.
The root pass is the foundation of every pipe weld.
169.
Fill passes build weld strength.
170.
The cap protects and completes the joint.
171.
Different electrodes are designed for different materials.
172.
Low-hydrogen electrodes help reduce cracking.
173.
Some electrodes require heated storage ovens.
174.
Moisture can ruin welding consumables.
175.
Preheat reduces the risk of cracking in many materials.
176.
Post-weld heat treatment relieves residual stress.
177.
Some alloy steels require strict temperature control.
178.
Stainless steel contamination can lead to corrosion.
179.
Dedicated stainless tools help prevent contamination.
180.
Welders must understand metallurgy—not just how to strike an arc.
181.
Visual inspection is the first step in weld quality.
182.
Radiographic testing (X-ray) examines internal weld quality.
183.
Ultrasonic testing detects internal flaws.
184.
Magnetic particle testing finds surface cracks in ferromagnetic materials.
185.
Liquid penetrant testing works on non-porous materials.
186.
Some refinery welds require 100% nondestructive examination (NDE).
187.
Welding Procedure Specifications (WPS) define how a weld must be made.
188.
Procedure Qualification Records (PQR) validate welding procedures.
189.
Welder Performance Qualifications verify a welder’s ability.
190.
Every qualified welder must follow the approved WPS.
191.
Even experienced welders continue learning throughout their careers.
192.
Arc blow can affect weld quality in DC welding.
193.
Wind protection is essential for many welding processes.
194.
Poor grounding creates unstable arcs.
195.
Good body positioning improves weld consistency.
196.
Patience often produces better welds than speed.
197.
Grinding is part of welding—not a sign of failure.
198.
The highest-quality weld is often the one no one notices because it simply performs flawlessly.
199.
Every refinery depends on welds that can safely withstand pressure, temperature, vibration, and decades of service.
200.
The best welders earn their reputation through consistency, discipline, and producing safe, code-compliant welds every single day.
