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CONSTRUCTION PROCESSES

CONSTRUCTION PROCESSES

Introduction:

We constantly analyze our gas pipeline system to ensure it meets safety and reliability standards —in neighborhoods both old and new. As part of our ongoing commitment to ensure the safest, most reliable delivery of natural gas to all of our customers, we will continue to replace and remediate portions of our pipeline system in communities across Virginia, Maryland, and Washington, D.C. as necessary.  To see if your neighborhood will be immediately impacted by construction activity, please visit our interactive map

The pipelines that bring natural gas into your home or business can be copper, steel, cast iron or plastic. Just like other important parts of the infrastructure in our communities, such as highways and bridges, age and condition can impact their safety and reliability.  While we continue to maintain these facilities 24 hours a day, 365 days a year, at some point their replacement/remediation becomes prudent.  This is typically accomplished by installing new much longer lasting, specially-designed, polyethylene pipe.

The Pipeline Replacement/Remediation Process:

In order to understand the construction process involved in replacing or remediating the underground natural gas piping system, one should know the three basic piping terms: main line, service line, and gas meter.   A main line is the pipe that carries natural gas to multiple customers and extended areas.  These lines are typically located under the street, alley, or sidewalk, whereas, a service line is the pipe that runs from the main line to individual customers’ gas meters.  This is the line that delivers gas to each residential, commercial, or industrial building.  A gas meter is the device/apparatus that is connected to the service line which measures the volume of gas used by a customer for a particular period of time and is utilized to accurately bill each customer based upon their gas usage. 

Below is a diagram depicting the terms described above.

Main line and service line installation

Figure 1:  Typical main line and service line installation.  Main Line, Service Line, and Gas Meter.

The underground main and service lines serving your community were typically installed three to four feet below the surface.  In order for a Washington Gas’ construction crews to replace/remediate these lines, an excavation in the street and in your property is usually necessary. 

While Washington Gas makes every reasonable effort to minimize disturbance in your community and your property, the type and size of the excavations depends upon the installation method necessary for each project.  The various types of excavation and the corresponding gas piping installation method will be further discussed in detail below.  

In most cases, the following scope of work will occur during the performance of the gas line replacement/remediation project in your neighborhood:

  1. Replace the gas main line (if applicable).
  2. Replace the gas service line(s) (if applicable).
  3. Move interior Gas Meters from inside to outside.
  4. Perform temporary Restoration to areas impacted by construction activities.
  5. Perform permanent final restoration to impacted areas.

The pipeline replacement/remediation construction process can be broken down into three major phases:

  1. Pre-Construction or Notification Phase,
  2. Active Construction/Excavation Phase, and
  3. Post Construction or Restoration Phase.

 

  • Pre-Construction/Notification Phase

    In addition to this website, Washington Gas will also notify the account holder on record via U.S. mail that the work in your neighborhood is scheduled to begin. A letter detailing a project overview of the construction process, as well as the names and contact numbers of assigned project personnel that can answer any project questions during working hours will be sent. The notification letter will be followed by a door hanger and a face-to-face visit by our construction representative or contractor to discuss the construction process and to answer any questions you might have. If no one is home, a notification card is left behind with contact information to call us to schedule your service replacement.

    In some instances, we will need to secure sufficient work space in the street to conduct the needed construction activity. As necessary “No Parking” sign(s) will be posted, typically at least 72 hours in advance within the affected work area. Lastly, before the construction work begins, a representative from Miss Utility will identify and locate all of the underground utility lines within your neighborhood with paint marks and / or flags as required by law. These paint marks will help minimize any potential damages to underground utility lines during excavation.

  • Active Construction/Excavation

    This is the phase of the project where the actual work to replace/remediate the existing gas main and service lines with modern material are performed.  As mentioned above, the type, size, and number of excavation varies based on the installation method necessary for the project. 

    These various installation methods are as follows:

    Main

    1. Main Direct Bury Method
    2. Main Insertion Method - wherein the new gas line is inserted through the existing gas main.
    3. Main Directional Drill Method –utilized to the extent practicable to minimize the necessary restoration.

    Service

    1. Service Insert or
    2. Direct Bury Method

                          


     It is important to note that regardless of the construction technique employed there are common activities to all which include:

    1. Maintenance of Traffic
      The preparation for an excavation as well as the actual excavation work will often involve the closure of sidewalk(s) and/or street lane(s). This is accomplished by utilizing approved and permitted temporary traffic control measures to facilitate the safe flow of pedestrians and traffic as well as the most expeditious execution of our work.
    2. Placement of Steel Plates
      Steel plates may be placed and maintained at the excavation locations at the end of the workday to protect vehicles and pedestrians from the excavated areas as well as to maintain traffic flow to the extent possible.
    3. Management of Excavated Materials/ Spoils
      The excavated material or “spoils” will be evaluated to see if they can be reused to fill the excavation aka. “Backfilling”. Excess or unusable materials or spoils will not be stockpiled in the job site, but rather will be hauled away and an approved backfill material brought in to complete the burial or “backfilling” of the gas line(s). In many/most cases for service line replacement/remediation, the native top soils from the excavation on your property will be utilized to backfill any excavation on your property.Some select material may be utilized directly around the gas piping with the remainder being the native soil originally removed.
    4. Control of Erosion and Sediments
      To protect sediments from getting into the storm drains, proper erosion and sediment control measures will be taken as necessary per regulation.
    5. Management and Upkeep of Staging Area
      In order to facilitate the efficient execution of a project a permitted temporary staging/storage area where necessary construction materials, such as pipes and fittings, select backfill materials, cold mix asphalt, and construction equipment will be established.A portable sanitary facility for the construction workers will be placed at this staging area as necessary.

    Restoration of Hard Surfaces and Landscaping or Disruptions to Property

    Initial temporary restoration of areas impacted by construction activities will be completed and maintained as necessary until the final and permanent restoration is performed. Permanent restorations activities will automatically be initiated by our workers once the gas line work in an area is completed.  This will occur as soon as practicable but may be delayed as paving operations are effected/limited by weather.  This process is discussed in the post-construction / restoration phase. 

  • Post Construction Restoration

    This is the final phase of the construction process where we mobilize our paving crews to permanently restore the roadway pavement and other hard surfaces in your yard that were disturbed by our pipeline crew while performing their work.  Before our paving crew begins their work, they will notify your neighborhood in advance by posting signs or placing door hangers on your door, and in some cases, when paving work will be in the roadway, will post “no parking” signs in areas as needed.  Our representative will also make arrangements with you to address any restoration issues needed to be performed in your yard.

    It is important to note that when restoring cuts made on a roadway or sidewalk pavement, the placement of concrete or asphalt mixtures is weather and temperature dependent.  In the interim, we will continue to maintain the temporary paving patches until the final pavement restoration is performed. In many cases, the paving work will require to temporarily close a sidewalk or street lane for traffic.  This is accomplished by utilizing the approved temporary traffic control measures to facilitate a safe and expeditious execution of work by our paving restoration crew. 

    Depending upon the weather, scope, and the extent of restoration, the work can be completed in several days.  For example, it takes two trips/mobilizations for our paving crew to perform restoration on a roadway structure with concrete base and an asphalt surface versus one trip/ mobilization for a roadway structure that has an aggregate base and a full-depth asphalt.  The first scenario requires placement and curing of the concrete base for strength prior to milling the existing asphalt surface and overlaying it with new asphalt.  It will take several days to cure the concrete base; steel plates will be temporarily placed over the concrete base to protect it from vehicular loads during its curing process.  The second scenario only requires milling of the surface of existing full-depth asphalt roadway and overlaying it with new asphalt.  Finally, as soon as our paving contractor completes the roadway surface restoration, the pavement marking or line striping will then be restored.

    Ahead of Paving (AOP) Projects

    Infrastructure improvement and renovation projects by others, such as roadway reconstruction or resurfacing and storm drain improvements, within the public right of way initiated by federal, state, and local transportation agencies, may involve utility line relocation and/or abandonment in advance of their work to facilitate the safe and efficient execution of their projects.  These types of work are generally referred to as Ahead of Paving (AOP) projects.  It is important to note that for these projects the paving cuts by Washington Gas’ contractor will be temporarily restored and maintained until the AOP project, e.g. roadway improvement project, is performed by the state or local agencies which will carry out the permanent paving restoration.

Main Construction Techniques

  • Main Direct Bury Method

    As the name implies, this construction technique involves excavating a trench to install the new gas lines. Typically the trench for the main line is excavated within the public right-of-way and to the extent possible outside of the roadway. Gas service lines are also installed in this fashion with the excavated trench largely running perpendicular to the main trench to the customers meter location.

    Restore Street Cuts and Landscaping or Disruptions to Property

    Permanent restorations will occur as soon as practicable or when weather permits. This process will be discussed in length in the post-construction/restoration phase. However, temporary restoration of the street cuts and your yard will be done and maintained until the final and permanent restoration is performed.

  • Main Insert Method

    This method for replacing/remediating gas main lines can be used effectively in some instances when extending medium pressure gas through existing low pressure gas mains. The higher pressure of the gas within these lines offers improvements in reliability as well as facilitates the insertion of a smaller diameter pipe, with the same or greater gas carrying capacity, through the old gas main line.
  • Main Directional Drill Method Replacement and Service Line Replacement Via Keyhole

    This trenchless technique for installation of main line can be utilized in areas outside of the roadway where there is an adequate space below the surface to allow this technique. Using this method will minimize excavation in the street and in most circumstances, will help facilitate for the speedy completion of the project as compared to other installation methods.

    Relight Appliances

    After the gas is introduced to the new main line and the affected services are transferred over, we will again need access to your house to finally relight your appliances. If you are not at home at that time, we will leave a note on your door with information and a telephone number to call to make arrangement for the relight of your appliances.

    A typical main line insertion process that includes service line transfers and relights is primarily constrained by the number of affected services that a crew can work within one day.

Service Construction Techniques

  • Insert or Direct Bury - Service

    Replace the Service Line and Move the Inside Meter to Outside

    This process is often done in conjunction with the main line replacement/remediation. In this process, our construction representative will make arrangements to gain access to your house as we need to turn off the gas while we work on the service line and gas meter. Note: please inform the construction representative if you have plans to change or install new gas appliances so we can make sure to size any new service line with this in mind. In some instances, the existing service line is of acceptable material and simply needs to be transferred to the new gas main line. In other instances, the existing service line is of a material and age which warrants full replacement. In these instances, a new polyethylene gas service line will be installed. The methods for replacement are insertion method and direct bury method.

    1. Move Gas Meter (If Applicable) 
    In instances where the gas meter is inside, we will move them outside as close as possible to where the existing service line was located. In cases when we replace the main and service lines and increase the delivery pressure, an additional inline piece of equipment known as a pressure regulator will be installed just before the gas meter. In situations where Washington Gas determines it is not practicable to move the inside gas meter to the exterior, a vent line will need to be installed from the pressure regulator to the exterior of the home. The termination point of this vent line is governed by code and must maintain a specified distance from openable doors, sources of ignition etc. as it functions to vent gas if an unsafe condition arises.

    2. Relight Appliances
    After the completion of the service line’s replacement and meter move, we will again need access to your house to relight your appliances. If you are not at home at that time, we will leave a note on your door with information and a telephone number to call to make arrangement for the relight of your appliances.

    Typically the entire process replacing/remediating a residential service line will occur within the same day.
  • Meter Moves

    For safety and accessibility reasons, the existing inside/indoor meter and its components, such as regulators, vents, relief valves, etc., are to be relocated to the outside/exterior of the residential or commercial building. The best possible location of the meter and its components is selected with consideration for safety, accessibility for reading and maintenance, and for aesthetic reason where minimal disruption to customer’s yard is preferred. Wall brackets and protective guards are installed when required on and around the meter to safeguard it from damages due external forces such as vehicles or earth movements.

    It is important to know that this move/relocation is necessary due to the following:

    • The meter and its components are easily accessible for shut-off by the emergency response crews in the event of gas leaks or fire;
    • It is readily accessible and less disruptive to the customer and company crews when performing routine maintenance functions, such as meter reading and inspection, leak survey, and future meter (or its components) replacement activities. For meters installed with automatic/remote reading equipment, the batteries are also routinely replaced and access to this equipment is needed; and
    • In many cases, where the existing low-pressure service is replaced with intermediate (medium) pressure, the relocation/move of the existing inside/indoor meters to outside will eliminate the installation of the required vent pipe, which is needed for safety, from the inside meter to the outside building wall.

    The cost of this relocation when performed in conjunction with the projects has no direct expense to the customer. The company’s representative or its contractor will work with you to schedule the work. Typically, this work takes approximately one day, where the gas is shut off first thing in the morning and turned back in service by the evening.

What do the various colored markings in the street mean?

The various colored markings throughout the neighborhood are done by Miss Utility. They mark the location of all utilities (e.g., sewer, water, electric, gas, etc.). The paint is temporary, solvent, biodegradable and either chalk or water based.

They do not indicate where the crews will be digging –  but simply let the crews know where all utilities are located underground.  It is the law that Washington Gas has to call Miss Utility and have all the utilities marked.

For more information, visit the Miss Utility website.


 

COLOR CODE

 

 

WHITE - Proposed Excavation

PMS 806˜


PINK - Temporary Survey Markings

PMS 1795˜

 

RED - Electric Power Lines, Cables, Conduit and Lighting Cables

PMS 108

 

YELLOW - Gas, Oil, Steam, Petroleum or Gaseous Materials

PMS 144˜

 

ORANGE - Communication, Alarm or Signal Lines, Cables or Conduit

13.5 parts process, 2.5 parts reflex

 

BLUE - Potable Water

PMS 253

 

PURPLE - Reclaimed Water, Irrigation and Slurry Lines

PMS 3415

 

GREEN - Sewers and Drain Lines

Contact Us:

Jack Morrow, Director – DC & MD Construction
703-750-4420
jmorrow@washgas.com


Washington, D.C. Construction:

Frank Frost, Manager
202-624-9058
ffrost@washgas.com


Dave Thomas, Manager

703-750-4263
dthomas@washgas.com


Maryland Construction:

Brendan Gamble, Sr. Manager
202-624-6439
bgamble@washgas.com


Mike Riley, Manager

202-624-6438
mriley@washgas.com


Reggie Wilson, Manager

202-624-6164
rwilson@washgas.com


Virginia Construction:

Kris Kelley, Director – VA Construction    
703-750-7710
kkelley@washgas.com


Joel Holland, Manager

703-750-7518
jholland@washgas.com


Les Lanier, Manager

703-750-4969
llanier@washgas.com


Kelcey Wilson, Manager

703-750-4483
kwilson@washgas.com