Parallel Line Explosive Charge

Parallel explosive charge are complex methods which have been simplified in many cases to into equivalent parallel line or point sources. The estimate of the standard error for parallel equations can be as high as 34%; However, if the standoff distance between the pipe and explosive line is greater, then it can be approximated by a single point source.


The minimum distance from the pipeline to the nearest explosive charge must be greater than two times the outside pipe diameter.

𝑅 − Distance from the Charge to the Pipeline(ft)

𝑃 − MAOP−Maximum Allowable Operating Pressure(psi)

𝐷 − Pipeline Outside Diameter(in)

𝑡 − Pipe Wall Thickness(in)

𝑆_ℎ − Hoop Stress(psi)

𝐿 = 𝑁₁𝐿₁

𝑊 = 𝑁₁𝑊₁

𝐿 − Total Length of Explosive Line(ft)

𝐿₁ − Spacing Length Between Charges in Explosive Line(ft)

𝑊 − Total Charge Weight(lbs)

𝑊₁ − Weight of Single Charge(lbs)

𝑁₁ − Number of Charges in Explosive Line

𝑆_𝑐 − Maximum Circumferential = 𝑆_𝑙 − Maximum Longitudinal Stress(psi)

𝑛 − Equivalent Energy Release Ratio

𝑊 − Weight of Single Charge(lbs)

𝐸 − Modulus of Elasticity

𝑡 − Pipe Wall Thickness(in)

𝑆_𝑡 − Combined Hoop and Circumferential Stress(psi)

Blasting Conditions for combined Stress Level

𝐶𝑎𝑙𝑆𝑀𝑌𝑆 >%𝑆𝑀𝑌𝑆 − NOT ACCEPTABLE/𝐶𝑎𝑙𝑆𝑀𝑌𝑆 <%𝑆𝑀𝑌𝑆 − ACCEPTABLE

Input Parameters

1. To create a new case, click the “Add Case” button
2. Select the Parallel Line Explosive Charge application from the Pipe Blast module.
3. Enter Case Name, Location, Date, and any necessary notes.
4. Fill out all required fields.
5. Make sure the values you are inputting are in the correct units.
6. Click the CALCULATE button.

• Pipe Outside Diameter
• Pipe Wall Thickness
• Specified Minimum Yield Strength
• Maximum Allowable Combined Stress Level – SMYS
• Manufacturer
• Explosive Type
• Equivalent energy release ratio
• MAOP – Maximum Allowable Operating Pressure
• N1 – Number of Charges in Explosive Line
• L1 – Spacing Length Between Charges in Explosive Line
• W1 – Weight of Single Charge
• n – Equivalent Energy Release Ratio
• R – Distance of the Charge to Pipeline

Outputs/Reports

1. View the results.
2. If an input parameter needs to be edited be sure to hit the CALCULATE button after the change.
3. To SAVE, fill out all required case details then click the SAVE button.
4. To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
5. To generate a REPORT, click the REPORT button.
6. The user may export the Case/Report by clicking the Export to Excel/PowerPoint icon.
7. To delete a case, click the DELETE icon near the top of the widget.

• Total Length of Explosive Line
• Total Charge Weight
• Sh – Hoop Stress
• Sc-Maximum Circumferential = Sl-Maximum Longitudinal Stress
• St – Combined Hoop && Circumferential Stress
• S – Total Combined Stress
• Calculated Percent of SMYS
• Blasting Conditions for Combined Stress Level:

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