Frequently Asked Questions

Between 4 and 6 hours start-to-finish, per pipe sample. This includes all procedures of the HSD tester, full chemistry sampling and in-situ microscopy of the pipe material.

What is the total time on-site to test a pipe?

2-week advance notice with final confirmation by Thursday prior to the first week of testing.

How much advance notice do you need to mobilize to the field?

OPERATIONS / LOGISTICS

Yes: two HSD-trained and certified Field Technicians per crew.

How many technicians on a crew? Can we utilize one of our technicians?

Expedited reports are issued within 24 to 48 hours of completion of on-site testing. Expedited reports must be requested in advance of the project date and require an additional fee.

What are my options to shorten turnaround time for test data?

Reports can be customized using several add-ons and pre-developed options built-in to the standard HSD reporting process. One-time fee for further customization or custom reporting template.

Can I request customized reports?

Reporting & Analytics

Preliminary report containing raw data collected is available immediately via MMTConnect software. The final TVC record is available within 7-to-10 business days, which pipe body chemistry, microstructure grain size, ERW seam type and heat treatment assessment, and pipe body grade (e.g. yield and ultimate tensile strength).

How long does it take to receive the final report?

The HSD is the only field instrumentation that performs frictional sliding to imprint multiple long shallow grooves on the pipe surface, which enables the collection of hundreds of measurements from a single test to sample a greater volume of material and provide reliable averages.

In addition, the HSD measures the material response at targeted levels of deformation that create a representative stress-strain condition that is closer to the initial yield and ultimate tensile strength of the material, reducing the extrapolation that is required when compared to indentation-based methods.

These fundamental advantages are further enhanced by the MMT validation database used to develop predictive analytics that consider HSD results, pipe body chemistry, steel grain size, and pipe construction. This database is constantly growing, and currently includes over 200 pipe joints covering a broad range of pipe attributes, grades, and vintages.

The HSD process outperforms alternative methods, due to:

What makes the HSD testing more accurate and reliable than any other option on the market?

What type of seam welds can HSD identify?

What are the procedures and specifications for testing elbows, tees and other complex geometries?

science & technology

● Stronger scientific basis behind the measurements
● Superior implementation of the measurement method with field equipment that performs in the field as good as in the lab
● Single package that includes mechanical testing, chemistry and microstructure of the pipeline steel
● Most developed pipeline asset database of validation comps
● Best-in-class analytics

HSD can identify all known seam types, including: submerged-arc-welded (SAW), flash-welded, lap-welded, seamless, and electric-resistance-welded (ERW) pipes. For ERW seams, HSD further determines low frequency (LF) or high frequency (HF) manufacturing process, and whether an effective post-weld-heat-treatment was applied.   

The HSD Tester can be applied to different pipe geometries and fittings for various applications:

● Straight Pipe Joints: Size Range - 3 inch OD and larger; Testing is conducted in two testing locations around the circumference of the pipe.
● Elbows: Size Range - 8 inch OD and greater, both 90° and 45° bends; Drawings or dimensional information preferred beforehand; Testing is conducted at the extrados and crown of the sample.
● Tee Joints: Size Range - 3 inch OD and larger, requires minimum of 12 inches unobstructed straight pipe; Drawings or dimensional information preferred beforehand.
● Reducers: Capabilities dependent on length and transition form larger diameter to smaller diameter. More gradual transitions will enable testing.

The output from testing complex geometries can be processed using line pipe equations (expected to be a lower bound for grade) and/or seamless pipes (expected to be the upper bound for grade).

Why should I account for UTS when determining grade?

The new gas transmission rule specifies that grade verification must consider measurement of both yield strength and ultimate tensile strength (UTS). This requirement is confirmed through a FAQ posted by PHMSA.

The HSD tester is superior to alternative techniques for determining UTS. Although HSD provides comparable accuracy and measurement uncertainty for estimating both yield strength and UTS (3.0 and 2.9 ksi at 80% confidence, respectively), alternative methods have significantly higher uncertainty for predicting UTS, which leads to more inconclusive grade verification outcomes, and the need for additional test locations to verify material properties (when applied within an alternative sampling plan).

This is especially true for lower strength grades (e.g. B, X42) -- where the difference between the measured UTS and specified minimum strength requirement in API 5L is limited. An analysis by MMT of over 100 pipeline populations using an alternative sampling plan meeting the requirements of 192.607(e)(5) found that 45% of populations would require more test locations to verify UTS than yield strength.

The HSD Tester is constantly collecting measurements as the grooves from the frictional sliding process are being generated. As a result, a single HSD Test collects hundreds of measurements from every groove. These measurements are then divided into 10 subsets of equal distance along the length of the test. Each of these resulting subsets qualifies as a sampling. Additionally, duplicate HSD tests are performed in two different testing locations on every pipe. A single HSD report includes significantly more measurements than the minimums required by the regulations.

How does the HSD unit meet the 607 requirement and compare with the stated “five samples on two different quadrants of pipe?”

PHMSA Regulatory compiance

MMT has developed the framework for an Alternative Sampling Plan that meets the requirements of 192.607(e)(5) -- which allows operators to benefit from the reduced uncertainty of the HSD process to potentially reduce the required number of test locations to verify material grade for a pipeline population. To be implemented, this approach must be submitted to PHMSA through the notification process outlined in 192.18. Contact the MMT Reporting group (reporting@bymmt.com) to discuss details of this statistical process and next steps. 

Can MMT support an operator with interest in submitting an alternative sampling plan?

Field temperatures and humidity do not significantly impact HSD testing and associated NDE data collection. The HSD strength estimates have been evaluated for surface temperatures ranging from 0°F to 120°F and a temperature-based strength correction can be applied. Humidity does not affect HSD testing, but condensation on the pipe surface can reduce the quality of seam and microstructure etch and images. Field conditions have never prevented the reporting of test results. 

Does the HSD work in inclement weather and abnormal conditions, such as cold weather or condensation on the pipe?

equipment & instrumentation

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