Question 1

What are the most common cutting practices used in decommissioning?

Accepted Answer

Common cutting practices are:
 • Mechanical cutting (diamond wire sawing, band saws, circular saws)
 • Thermal cutting (oxy-fuel, plasma, and laser cutting)
 • Abrasive cutting (grinders, waterjet cutting)
 • Explosive cutting (used in controlled demolitions)

Question 2

What precautions should be taken during cutting and sawing operations?

Accepted Answer

• Use protective gear (gloves, goggles, fire-resistant clothing)
 • Adequate ventilation should be provided to control fumes
 • Spark and debris control should be done to prevent fire hazards
 • Adhere to lockout/tagout (LOTO) procedures to prevent accidental equipment triggering

Question 3

Which saws are most applicable for decommissioning work?

Accepted Answer

Diamond wire saws – Applied to use with thick metal and concrete structures
Band saws – Best for slicing steel beams and pipes
Reciprocating saws – Suitable for limited cutting in multiple materials
Cold saws – Achieve clean cuts with little heat and high accuracy

Question 4

How is it possible to cut underwater for offshore and pipeline decommissioning?

Accepted Answer

Diamond wire saws or hydraulic shears are used for heavy pipes
 Oxy-arc cutting diver-operated thermal cutting tools are used in deep water
 Remotely operated vehicles (ROVs) cut in deep depths

Question 5

What are the challenges in cutting materials like steel, concrete, and composite structures?

Accepted Answer

Steel – Gives sparks and heat, requires cooling or special techniques
Concrete – Creates dust and requires powerful cutting tools
Composites – Brittle and should be cut with specialized blades so as not to break

Question 6

How do mechanical and thermal cutting processes differ from one another?

Accepted Answer

Mechanical cutting uses sawing, grinding, or shears and does not generate intense heat.
Thermal cutting (laser, plasma, oxy-fuel) heats or melts through material to be quicker, but also in need of heat-resistant precautions.

Question 7

Under what conditions is diamond wire sawing preferable to traditional methods?

Accepted Answer

Diamond wire sawing is appropriate for:
Cutting thick metal or concrete where precision is needed
Underwater cutting
Low-vibration use to avoid structure damage

Question 8

How does robotic cutting technology improve decommissioning efficiency?

Accepted Answer

Reduces worker exposure to hazardous conditions
Increases cutting speed and precision
Enables cutting in constrained areas or underwater without the use of divers

Question 9

What are the advantages and constraints of applying plasma cutting in decommissioning?

Accepted Answer

Advantages: Rapid, efficient on thick metals, minimal waste
Constraints: Creates heat, requires ventilation, can't be used on all materials

Question 10

What is the use of waterjet cutting in decommissioning poisonous buildings?

Accepted Answer

Cold cutting prevents heat destruction or explosions
Precise cutting reduces waste
Able to cut different materials (metals, composites, concrete)

Question 11

How does cutting process impact environmental safety?

Accepted Answer

Thermal cutting produces fumes and heat, requiring ventilation
Mechanical cutting generates dust, requiring water suppression
Underwater cutting can disturb marine ecosystems, requiring steps to reduce it

Question 12

What control is placed on dust, sparks, and fumes during cutting?

Accepted Answer

Water suppression systems decrease dust
Fume extractors remove hazardous fumes
Fire blankets hold back sparks in enclosed spaces

Question 13

How is fire danger controlled when cutting pipes with combustible residues?

Accepted Answer

Purging pipes with inert gas prior to cutting
Cold-cutting techniques such as waterjet cutting
Having fire extinguishers and emergency response on hand on site

Question 14

What are optimal practices for cutting radioactive or contaminated materials?

Accepted Answer

Utilize remote-controlled cutting equipment to keep exposure low
Cut in controlled environments with appropriate containment
Follow strict decontamination and disposal protocols

Question 15

How is noise and vibration minimized for mass cutting activities?

Accepted Answer

Diamond wire or waterjet cutting, which produce lower vibration
Use of sound barriers in controlled environments
Work at times of low impact in populated regions

Pipeline & Offshore Cutting

Question 16

How are offshore subsea pipelines cut during offshore decommissioning?

Accepted Answer

Diver-cutting (oxy-arc or hydraulic saws)
ROV-mounted saws for deep water application
Diamond wire saws for cutting precision

Question 17

What are the unique precautions needed when cutting buried or submerged pipelines?

Accepted Answer

Protection of sediment from disturbance to prevent harm to marine life
Pre-cut leak monitoring
Undercutting to prevent collapse

Question 18

What tools are used for cutting thick-walled steel pipelines safely?

Accepted Answer

Hydraulic shears for clean, high-power cuts
Plasma cutters for quick cutting metal
Diamond wire saws for low-impact, precise cuts

Question 19

How do divers use cutting equipment safely underwater?

Accepted Answer

Using insulated tools to prevent electric shoc
Wearing specialized dive suits for protection
Following buddy system protocols for emergency assistance

Question 20

What other cutting methods can be used if conventional saws cannot be employed?

Accepted Answer

Explosive cutting in massive demolitions
Abrasive waterjet cutting in sensitive or dangerous materials
ROV-facilitated cutting when divers cannot work safely

FAQ's

Frequently Asked Questions