Pipeline & Gas Journal
December issue 1999:

P&GJ’s 34th Pipe Report

Gas Distribution  Spending Continues to Grow

by Maretta Tubb, Managing Editor, Pipeline & Gas Journal

Spurred by the nation’s demand for natural gas, U.S. gas distribution spending continues to grow. Response to P&GJ’s 34th Pipeline Survey Report indicates gas distribution spending to serve new customers and maintain and upgrade existing systems will total an estimated $7 billion this year. Of this, $3.4 billion will be spent for new construction, while spending to rehabilitate repair and replace the 955,000 miles of distribution lines, meters, regulators, valves, gauges, cathodic protection, SCADA networks and peakshaving facilities owned by the nation’s gas utility industry totals $3.5 billion.

New construction and 3Rs spending in the new millennium is expected to be still higher, totaling an estimated $7.4 billion.

Given the high costs associated with meeting the nation’s growing demand for natural gas, it is not surprising that the nation’s gas industry has long relied on the use of plastic pipe which is easier to handle and join and eliminates the need for corrosion protection. At this time, the Code of Federal Regulations (CFR) prevents LDCs from using plastic pipe over 100 psi. This precludes its use in trunk lines and other applications that would require intermediate pressure (i.e., 100- to 500 psi). The industry has petitioned the Department of Transportation’s Office of Pipeline Safety to remove the 100 psi limitation and to raise the design factor to 0.40, making it comparable to steel pipe in Class 4 locations. If these petitions are accepted, it would allow LDCs to use plastic pipe to its maximum design pressure as limited by the materials hydrostatic design rating(1). 
While other plastic materials are available, polyethylene (PE) pipe remains the top choice for cost-effective installation of new gas mains and services. According to Michael M. Mamoun, principal project manager, GRI, the U.S. gas distribution industry will account for 32,000 to 36,000 miles of new PE installations this year.

Mains & Services
P&GJ also surveyed gas utility industry representatives about plans for new mains and services and installation costs for new plastic and steel mains. Figures provided by survey participants indicate 12,761 miles of new mains will be added this year along with 7,622 mile of replacement mains, 10,841 miles of new services and 10,554 miles of replacement service lines. All totaled, new and replacement mains and services are expected to amount to 41,778 miles this year. 
Of those reporting average cost per foot by pipe diameter to install plastic mains, the costs ranged from $2 to $30 per foot for 2-inch; $5 to $12 for 3-inch; $4 to $40 for 4-inch; and $6 to $60 for 6-inch. The cost for 8-inch, 10-inch and 12-inch plastic ranged from $17.50 to $70.
A Texas-based LDC that reported average plastic main installation costs per mile provided these figures: 2-inch, $30,000; 4-inch, $40,000; and 6-inch, $60,000.

As to main and service repairs, a North Carolina company that installs 400 to 500 services a year said it relied totally on Perfection stab fitting for all main and service repairs, two inches and smaller. Since 1992, they have successfully used Perfection bolt-on tapping tees and stab fitting for all plastic services.  

To help determine the cost of new services in developed and undeveloped areas, P&GJ looked to a GRI study that lists the following for 2-inch PE services:  $496 in undeveloped tracks; $1,543 in developed areas and approximately $5,600 in urban areas. The survey found the unit cost of main installed by direct burial as ranging from $4 foot to $160 foot and reported that joint trench installations could reduce costs in undeveloped areas by 30 percent vs. gas-only installations.
Noting that main size generally varies from 1 1/4-inch to 3-inch, the GRI study states that medium- or high density PE is used extensively by the gas distribution industry. Two-inch PE is apparently used about 85 percent of the time in undeveloped areas and accounts for 95 percent of all new main installations in developed areas. On the other hand, residential services vary from 1/2- to 3/4-inch, with the majority involving 5/8-inch tubing. Commercial and industrial services are larger in diameter, but constitute only a small portion of services installed at this time.

Although not tracked in the P&GJ survey, GRI’s survey shows that utilities rely on directional borings to install about 17 percent of all new main in developed areas.

Q&A Response 
As in past years, P&GJ survey recipients were asked to submit comments to a series of questions focusing on repairing and replacing cast iron and bare steel in existing systems,  fusion technology, the cost of finding and repairing leaky mains and plastic pipe failure. Survey findings and select comments addressing these and other survey questions follow.

Cast Iron & Bare Steel Replacement & Repairs
The replies to this question tell us that the majority of the long-term programs that started in the 1980s to remove and/or replace cast iron and bare steel in systems are now winding down. Of those commenting on replacement programs, almost 25 percent indicated plans called for replacing cast iron in systems by 2000 and bare steel by 2004 or 2005.  

A gas company in Ohio with a customer base of 428,500 reported initiating in-house programs in 1989 to address aging cast iron and bare steel in its system. The programs are set up to assign points to segments of pipe based on past leak history, age, size and pressure of the gas. The rating calculated for each segment is used to determine the replacement status of the pipe.

The company noted that it had purchased a Cast Iron Maintenance Optimization System (CMOS) and is in the process of sponsoring the development of a similar bare steel program. Both of these programs statistically predict leak and break activity based on static and dynamic variables of the pipe and its environment and provides a repair vs. replace comparison report. Stainless steel bands, cast iron saddles and sleeves, encapsulation and Perma Bond were listed by the company as methods being used to repair cast iron and bare steel in existing systems.

A small gas company in Arkansas is replacing cast iron in its system on a yearly basis. Plans call for all cast iron to be replaced within five years.
Typically, this year’s survey response finds that companies are using plastic in repair and rehab projects when possible. Other popular techniques being used to deal with cast iron and bare steel pipe repairs include repair clamps, joint seals, and weld repair techniques. Several companies indicated using both directional drilling and open cut to replace and/or make repairs.

Steel Main Costs
Once again, the majority of those surveyed reported higher spending to install new steel mains vs. plastic. The following listings reflect actual cost figures reported by companies to install steel mains: $2.70 to $40 per foot for 2-inch; $6 to $21.60 for 2 3/8-inch; $7.10 to $16 for 3 1/2-inch; $4.80 to 40 for 4-inch; $10 to $70 for 6-inch; $11 to $90 for 8-inch; $11 to $100 for 10-inch and approximately $100 for 12-inch.

Finding & Repairing Leaky Mains
For the most part, survey participants made it clear that quoting costs for finding and repairing leaky mains is not easy. Of those willing to provide finding and repair costs regardless of size, 18 percent provided the following as an average cost of finding and repairing a leaky main: $325; $525; $570; $575; $685; $775; $890; $1,000, and $1,025.

Those reporting finding/repair costs by size provided the following: 3/4- to 2-inch, $150 to $1,050; 3-inch, $360 to $1033; 4-inch, $109 to $1370; 6-inch, $510 to $1,305; 8- to 12-inch, $605 to $2,500.

Two LCDs reporting actual cost figures from recent jobs said they had spent $5,980 and more than $50,000, respectively. The $5,980 finding/repair cost reportedly came as a result of a leaky main under a roadway, while the more costly main repair was carried out in a highly congested urban location.

One gas/electric company with 120,000 customers listed $750 to $1,000 as its average cost of finding and repairing leaky mains. Another with 355,000 customers said $949 represented the average cost for repairing leaky mains. Locating costs were not included in the $949 figure. 

Fusion Technology  
Our question regarding fusion technology clearly indicates that butt-fusion remains the method of choice for making main connections, while electrofusion is preferred for making live main tie-ins, repairs and work in confined areas. Overall, companies reported no problems with the butt-fusion method, provided sufficient space existed to allow proper pipe alignment and pipe preparation. 
One LDC with just over 420,000 customers indicated that while the electrofusion method worked well, control box failures during the melt cycle had resulted in a number of bad fusion connections. Further, although they had experienced no problems with butt-fusion, the company was now using stab fittings and electrofusion on all fusion applications one-inch and smaller.

Conversely, a gas distribution utility in Texas that reported only positive results with electrofusion said it planned to begin using this method for all main installations.

Others found that the cost of  electrofusion presented problems. One company that uses  electrofusion in both the construction and repair of plastic pipe said, “We like this method very much and can only say that we wish it were not so expensive. Not all of our crews have this equipment simply because of cost.”

Plastic Pipe Failure
The majority of those surveyed indicated they had not experienced in-service plastic pipe failures. Of those reporting plastic pipe failures, almost 70 percent said the problems incurred had been isolated cases where the pipe was installed in rocky areas. Other commonly cited causes for pipe failure were: improper fusion techniques, third-party damage, improper bedding of the pipe, lightning and improper squeeze-off techniques.  

Companies located in Louisiana and New York both reported experiencing butt-fusion failure after the pipe had been in the ground about 10 years. One reporting several failures had this to say: “We successfully traced our failures to bad joint fusions that we were able to trace back to either improper temperatures or unclean heating irons.”

Needed Improvements To Equipment, Tools & Systems 
This year’s survey response shows that the gas utility industry would like to see improvements and technological advancements in a wide range of equipment and systems. The strongest need expressed was for pipe locating equipment capable of providing a better read on depth as opposed to just location.

Of those with specific equipment requests, a North Carolina based utility said “a battery powered electrofusion system would be great!”

Compact excavators for confined work space, non-destructive PE fusion testers and wireless PE pipe locators were among the most requested items.

Trenchless Issues
Companies addressing the trenchless issue said that while improvements are needed, this technology has the potential to reduce gas line installation, maintenance and rehabilitation costs by 50 percent or more.

Moreover, the comments point out that now more than ever the pressure is on to use no-dig technologies in the gas industry. Success will depend, however, on capital expenditures to fund equipment innovations and testing to predict pipe and joint failure and address pressing safety issues. P&GJ