In any building project (i.e., residential community, commercial or recreational facility, or shopping center), dry utility coordination is often required.
Dry utilities include cable, electric, telephone, natural gas, television, and fiber optics.
In this blog, we’ll discuss what comes with dry utility coordination and installation.
Let’s get started.
1. What are dry utilities?
Dry utilities construction in land development is the installation of electric, telephone, TV, internet, and gas in a community.
It occurs when we excavate, directional drill (as required), and install the required infrastructure for the above utilities.
That said, before dry utilities can be installed, precise placement, alignment, and routing of infrastructure lines must be devised to ensure they are properly installed.
In order to do this, site visits must occur and the site’s unique topography, slope angles, and soil conditions must be documented.
The engineered design will be delivered in the form of construction drawings based on these on-site conditions.
The construction drawings will include utility mapping, required materials, and detailed notations about how the installation will ensure compliance with all codes and regulations.
Most dry utility installation projects begin with digging a trench to house the utilities in question.
The next step is excavating the trench and using high-quality instruments to lay the bedding and install the utility.
Then, the cables are encased with shading materials to protect them from damage over time and finished with backfill services.
Finding a solid contractor who can coordinate, plan, and negotiate installations of electric, natural gas, telephone, CATV, communications, and data utilities is essential.
This is because dry utilities include electricity and gas, which can be dangerous to install.
Be sure to coordinate with an engineer and the relevant utilities and county/city departments as needed during construction.
You’ll also need to have inspections done at every step to ensure that all criteria are met.
2. What are wet utilities?
Wet utilities include any items that have to do with water, such as sewer, storm drain, and water systems.
Here are some of the most crucial elements:
Sewer mainlines: Typically the first and deepest utility.
This is so the waste won’t leak into any of the other lines.
The sewer system relies on gravity to help move sewage from homes to any off-site treatment facility.
Sometimes, a pump system can be put into place if the flow line is too flat.
Storm drain: This drain helps to direct excess rainwater offsite and discharge it into canals, rivers, lakes, reservoirs, seas, or oceans.
Water mainline: Generally the shallowest utility line.
This way, the sewer line below won’t be able to leak and contaminate the water mainline.
3. What is joint trenching?
Joint trenching is when different utilities are buried together in one trench.
You see this when pipes and cabling for gas, water, electricity, and telecommunication are run through a single trench in the ground together.
These may not only be main lines, but also service lines.
Joint trenching is also called common trenching, and it has several advantages, such as cost savings and the relief of underground congestion in areas of high development.
Joint trenching was first used by Commonwealth Edison and Illinois Bell in 1960.
Although it has not been universally adopted in the United States, the practice is increasing.
Some obstacles to universal adoption include conflicts of interest, difficulty in coordination, and issues with determining cost responsibility.
That said, joint trenching does help to save money in construction projects because it only requires the utility company to create one trench for underground utilities instead of several.
This practice also means that building projects can be offered more quickly to the market.
However, there are some potential problems with joint trenching.
The most prominent one being that water and electricity shouldn’t mix and neither should electrical currents and telecommunication lines.
Fortunately, codes have been written governing how the pipes and cables are laid in the trench to prevent any problems.
You must keep in mind adequate spacing between utilities as well as dirt buffers between lines.
4. Can I run electrical and gas in the same trench?
When electrical conductors are installed in the same trench as a gas line, it is recommended that the two systems be separated by 12 inches of well-tamped earth or a treated plank.
Here’s a quick guide to what utilities can share a joint trench if the following separations are maintained.
24 inches between gas and electric lines
12 inches between water and electric lines
24 inches between sewer and electric lines
12 inches between communications and electric lines
5. What is the recommended horizontal and vertical separation for underground utilities?
Every jurisdiction is going to have slightly different requirements, but below are the guidelines for the underground separation of pipelines and utilities from LA County:
Pipelines and utilities should not be installed closer than two feet from any other pipeline or utility
Pipelines and utilities should not be installed closer than three feet from any sewer line
Waterlines should not be installed closer than ten feet from a sewer line unless evidence of permission from the Division of Drinking Water (DDW) is provided
The following minimum depths of cover (below gutter flow line grade) are required:
For local streets
24 inches for service pipelines
30 inches for all pipelines transporting nonhazardous substances
30 inches for electrical facilities
42 inches for pipelines transporting hazardous substances
For master plan highways
24 inches for service pipelines
36 inches for pipelines transporting nonhazardous substances
42 inches for electrical facilities
42 inches for pipelines transporting hazardous substances
Note: If the lines are stacked on top of one another as part of a joint trench, then the normal vertical separation is 1 foot.
6. Who should you call before you dig for dry utilities?
The number 811 is the national call-before-you-dig phone number.
If you plan to start construction and put a shovel in the ground, you must call 811 a few business days before digging to request the approximate location of buried utilities be marked with paint or flags.
This way, you won’t unintentionally dig into an underground utility line.
Calling 811 helps to protect both you and your community.
Even if you think your project is “small,” it really is necessary to call 811.
It can be both dangerous and expensive to accidentally hit a buried line while digging.
You can end up disrupting utility service, needing to repair any utilities you hit or causing serious injury or death.
Contacting your local 811 center and waiting the required time for them to respond can help you circumvent any issues.
Here are some examples of projects that you’ll want to call 811 for…
When planting a small flower bed or bush
When installing a mailbox
When digging in a spot that was previously marked
When hiring a contractor or landscaper to do a digging project
When digging in a small area (and not your entire yard)
An underground utility line is damaged once every 6 minutes across the nation because people decide to dig without knowing the proper location of their lines.
Although these mistakes are often caused by larger excavation projects, it’s still possible to damage your dry utilities with a simple mailbox installation or small gardening project.
Be sure to speak to a professional utility inspector to avoid costly and dangerous potential damage to buried utility lines.
7. What’s the common color coding for marking underground utility lines?
The American Public Works Association provides Uniform Color Codes for temporary marking of underground utilities.
If you’re starting a building project and call 811, these are the colors that you’ll see used on your property.
Red: Electric power lines, cables, conduit, and lightning cables
Orange: Telecommunication, alarm, or signal lines, cable, or conduit
Yellow: Natural gas, oil, steam, petroleum, or other gaseous or flammable material
Green: Sewer and drain lines
Blue: Drinking water
Purple: Reclaimed water, irrigation, and slurry lines
Pink: Temporary survey markings, unknown/unidentified facilities
White: Proposed excavation limits or route
8. What’s the full dry utility installation process?
There are 10 basic steps for dry utility installation.
However, keep in mind that these are general steps and do not necessarily apply to every construction site.
Review the entire list and then select the steps that apply to your specific building site.
Inspect and pressure test any wet utility sewer lines that were previously installed
Have bacteriological testing done on the water system
Do a backfilling and compaction testing inspection on wet utilities
If relevant, do a potential second sewer and water system test
Wait to do any hard surface paving and finishing work until both wet and dry utilities have passed their final inspection and been approved
Once your inspections have occurred and your wet utilities have been approved, your dry utility trenching can occur
Note: there may be some instances in which your dry utility trenching may be permitted before any of these steps occur depending on your site conditions.
Next, ensure compliance with separation specifications of gas, electric, and telecommunication lines
Complete backfilling and compaction inspections and approval
Do final testing and inspections of wet and dry utilities installation as well as final approval
Remember, failure to comply with each and every specification on the approved construction plan will result in the suspension of construction until the problems are resolved, re-inspected, and approved
Dry utilities are an important part of the building process, but they’re nothing to mess around with.
Each land developer must take the dry utility process seriously and ensure they are in full compliance with the construction plan and all building codes.
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Disclaimer: we are not lawyers, accountants or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.