Tuesday, April 18, 2017

Part 49: Electrical Meter and Panel

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

The electrical service that supplies the building is provided in two stages. First as temporary power to a post installed by a licensed electrical contractor according to the site utilization plan. The post has a meter and grounded connections for use during construction.

MEP Phase – Insitebuilders

Connections to the main power source
The second stage of electrical service begins with the installation of the permanent meter and the main disconnect switches at the utility connection. The meter in mounted on an exterior wall of the building or as a free standing meter pedestal.

MEP Phase – Insitebuilders

The supply side of the meter is grounded to a copper rod driven into the ground or to a wire attached to the steel reinforcing in the foundation footer.

MEP Phase – Insitebuilders

When the meter is not mounted on an exterior wall, an underground cable runs from the utility connection to the service panel. An electrical conduit makes it easier to change or upgrade this cable to accommodate future needs.
MEP Phase – Insitebuilders

The anticipated loads for branch circuits and circuit breakers are determined by the electrical plan. These loads vary according to the number of receptacles and switches, as well as the specifications for the equipment and appliances that service the building.

For detailed information on basic electrical installations and residential wiring, see this DIYnetwork article.


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(To be continued…)

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The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders

Thursday, March 16, 2017

Part 48: Electrical and Energy Plan

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

The electrical plan for a residential building looks a lot more complicated than it really is. This is because licensed electrical contractors are careful to comply with local electrical codes that clearly specify materials, connection, and methods of installation.

The Electrical Plan
Electrical contractors use the electrical plan to understand the general layout of the building, note any special features or unusual conditions, and apply a rule of thumb based on the number of outlets, switches, fixtures, and special connections that are specified.

MEP Phase – Insitebuilders

The plan uses a standard set of symbols to show the location of the service connection, meter location, and interior distribution panels. It also shows the placement of outlets, switches, and the fixtures that will be required.

MEP Phase – Insitebuilders

The locations shown are not exact. Final placement is determined by the electrician and owner just before the subcontractor begins the work to rough-in the wiring and junction boxes.

The Service Panel Distributes Power
Circuits are balanced according to anticipated loads and the detailed requirements of state and local electrical codes. Generally, there are three types of circuits in a residential building.

MEP Phase – Insitebuilders

Wiring to all the required connections depends on the location of the service panel and the structural framing members that will be drilled for the installation.

MEP Phase – Insitebuilders

The total amperage entering the house from the utility provider is divided into branch circuits at the service panel. Each branch is designed to carry anticipated loads for receptacles, lights and switches, and dedicated fixtures on that circuit.

For safety, it’s important that an experienced, licensed electrical contractor calculate the loads represented by the electrical plan and install the correct circuit breakers.
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(To be continued…)

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The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.
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Insitebuilders

Thursday, February 16, 2017

Part 47: Heating Ventilation and Air Conditioning (HVAC)

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

Ducted air conditioning systems are easier to access and maintain than ductless systems because there’s a single outdoor unit and a single indoor air handler. Regular filter changes are required, but frequency depends on local conditions. The ducts themselves do not require cleaning under ordinary circumstances.

Ductless HVAC
On the other hand, ductless air conditioning systems, also known as “split systems, are flexible to install and efficient to operate. They include outdoor heat pumps that deliver conditioned refrigerant to indoor air handlers called fan coils, or blowers.

MEP Phase – Insitebuilders

The coils in the air handlers are cooled or heated by refrigerant supplied from the heat pumps. A circular fan blows room air over the coils to condition the space. The temperature of the coils and fan speeds are regulated by programmable controllers.

MEP Phase – Insitebuilders

Individual air handlers make it possible to heat or cool the spaces separately. This reduces energy demand and increases operational efficiency because the units are regulated independently.

MEP Phase – Insitebuilders

Control wiring as well as supply, return, and condensation tubing are installed as a bundled line-set within the framing. The line-sets are placed before interior finishes are completed. The distance from the outdoor unit to the indoor air handler is limited by the manufacturer and system specifications.

MEP Phase – Insitebuilders

Room layout and the location of the blowers must be carefully considered to minimize draft and stagnant pockets of air.

MEP Phase – Insitebuilders

A dryer cycle dehumidifies indoor air to improve room comfort. This reduces the need for conditioned air in a well insulated building.

In areas with high humidity, condensation must be carefully controlled to prevent damage and mold. A pan captures condensation below the coil and drains the moisture through flexible tubing to an outside sump.

MEP Phase – Insitebuilders

Direct ventilation is also necessary to reduce humidity and heating and cooling loads from point sources like bathrooms, appliances, kitchens, and high ceilings.

Power to the fans and control circuitry are supported by electrical wiring installed during the next phase of the construction. . .  





(To be continued…)

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The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.

Insitebuilders

Monday, January 16, 2017

Part 46: Heating Ventilation and Air Conditioning (HVAC)

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

Heating and ventilation systems are required by all local building codes because of health and safety concerns. Air conditioning is a relatively recent innovation and not required by code, though it is rarely omitted in hot or humid climates.

Ducted HVAC in a split system
Ducted HVAC is more expensive to install and operate but provides a more evenly distributed interior temperature. It is a two part system. An air handler is located in a closet inside the interior space. It contains a circular fan that draws air through a filter and over coils that contain heated or cooled “refrigerant.”

MEP Phase – Insitebuilders
An evaporator is located outside of the building. It houses a reversible compressor or heat pump that regulates the temperature of the refrigerant in the coils (See more about heat pumps here). MEP Phase – Insitebuilders
The fan in the air handler blows air over the coils and through sheet metal or foil ducts to registers in each room. Dampers and mixing boxes in the ductwork direct air flow according to zones controlled by a central thermostat.
MEP Phase – Insitebuilders
Most residential systems do not include return air ducts. Instead, an opening is located near the interior unit so air can be drawn back into the air handler to repeat the cycle. The result can be quieter and more energy efficient.  

Ducted versus Ductless Ducted HVAC requires careful planning prior to construction. The system evolved from central furnaces or fireplaces that distributed heated air through “tunnels” built into the walls of now antiquated structures. The conditioned air was lost through doors, windows, chimneys, and vents. No air was returned to the heat source.

MEP Phase – Insitebuilders
Ductless systems are much simpler. They send the “refrigerant” through copper tubing from an exterior unit to the coils in fan units located in each interior space (See Solar Colwood and next month’s illustrations).



 (To be continued…)  

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The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries. 

 Insitebuilders

Tuesday, December 20, 2016

Part 45: The Plumbing Works as a System

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)


The plumbing works as a system. Hot and cold water supplies are delivered through pressurized lines to the plumbing fixtures and unpressurized drains remove the waste to a sewerage disposal system.
MEP Phase – Insitebuilders

These drains rely on gravity and the correct slope to sustain the flow of liquid and solid waste. Vents relieve negative pressure created by the flow. 

Waste disposal includes drains and vent

The size and location of the drains and vents are determined by anticipated loads, site conditions, and the local building code.
MEP Phase – Insitebuilders

Plumbing fixtures are connected to branch and main lines and carry the waste to a sewer connection. Onsite septic systems are used where offsite sewerage treatment is not available. 
MEP Phase – Insitebuilders

The tank above the toilet bowl flushes waste into the drains. A p-trap is built into the porcelain base of the toilet. P-traps are used to block sewer gas from entering the house (See P-traps).
MEP Phase – Insitebuilders

The drains from the sinks are sized according to anticipated use. In most cases, the dishwasher and garbage disposal connect to the drain from the kitchen sink. Undercounter relief valves are used as vents for island sinks.

The connection to the grid


Special permits and meters are required to “hook-up” to water and gas mains. The meters are installed by the plumber and certified by the service provider. The utility companies control their services with lockable street-side shut off valves.
Emergency shut off valves are installed on the customer side of a gas meter in most earthquake regions.
MEP Phase – Insitebuilders
Though permits are required, sewer connections are not normally metered. Instead, a central waste line flows from the building to the treatment system (see Preconstruction). Note that backflow valves are required to block reverse flow from flooded sewers.    


(To be continued…)

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The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries. 
 Insitebuilders.com

Tuesday, November 15, 2016

Part 44: MEP Installation starts with the Plumbing

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

The supply lines that enter the house are installed to serve the mechanical, electrical, and plumbing (MEP) fixtures shown on the construction drawings.
MEP Phase – Insitebuilders
This includes power and communications cables, gas line, special fluids, and a main water line with hot and cold branch lines to the sinks, water closets, baths, and outside faucets. The work begins with the plumbing rough-in.

PEX supply lines  
Soldered copper tubing has been largely replaced by polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) tubes and fittings. Both of these synthetic plastic polymers are said to have latent environmental problems (see this article at Healthy Building Science).

Based on toxicity studies for water supply lines, flexible cross-linked polyethylene (PEX) tubing has shown to be a sustainable alternative to PVC installations. PEX tubing has gained in popularity because its simple installation makes it far less expensive, easier to maintain, and not as prone to environmental contamination.
MEP Phase – Insitebuilders
The PEX system shown in this example includes hot and cold water supplies in combination with recyclable high density polyethylene (HDPE) waste and vent pipes.

In cold climates, the main water supply runs below the local frost line, up into the building through a slab or insulated floor frame, into an insulated mechanical closet that houses a PEX distribution manifold.
MEP Phase – Insitebuilders
One branch of the water line flows from the manifold to a water heater and then back to the hot side of the manifold. Branch tubing then runs from the hot and cold sides of the manifold to shunt valves for each plumbing fixture.

The PEX tubing is color coded red and blue for hot and cold and is strung through the framing like wiring as a single continuous line. There are no inline joints or spliced connections to fail (see www.pexsupply.com).
MEP Phase – Insitebuilders

Be careful with gas lines With an abundance of caution, black iron gas lines are installed from the gas meter to the in-line hot water heater, dryer, and kitchen fixtures in lieu of the less expensive corrugated stainless steel tubing (CSST) normally found in most residential construction.

Building codes govern gas pipe material, size, and wall thickness for all underground service. Note that local codes also dictate the size and location of holes cut into the framing as well as the use of protective plates to prevent accidental punctures.    

(To be continued…)  


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The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries. 

 Insitebuilders  

Tuesday, October 18, 2016

A Quick Look at a Piece-based Construction Model

(Introduction, Syllabus, 1.Prelims, 1-4Precon, 2. Excavation, 3.Foundation, 4.Framing, 5.Close-In, 6.Roofing, 7.MEP, 8.Finish)

Before I begin the posts for the building systems, I’ve been asked to describe how the models for these illustrations were made and what programs I use for construction modeling.

Insitebuilders Tutorial
 All of the models in our books were built using an older, simpler, and “free” version of SketchUp v5 or v6 (download here)  

Overview of Construction Modeling 
A construction model is a builder’s tool and has nothing to do with 2D drafting, estimates, or quantity takeoffs. Instead, the models are “piece-based” and constructed just as they would be in the field. They are virtual simulations. Here are the three basic steps (and their tools)
  1. Move around the model space to orient yourself (Orbit, Pan, and Zoom
  2. Make the pieces for the assembly (Rectangle, Extrude, and Scale)
  3. Snap the pieces together in the sequence of construction (Move. Rotate, and Copy)
A Tutorial: Build a concrete block wall 
If you’re new to SketchUp open a new file and play with the program menus, dialog boxes, and navigation tools to see what they do.  

When ready:

Manufacture a block (with these tools):
  1. Drag out an 8,16 rectangle (Rectangle tool)
Insitebuilders Tutorial
  1. Extrude up 8 to form the block (Extrude tool)
Insitebuilders Tutorial
  1. Select and Group as a solid (Group tool)
  2. Name the block (Entity Information)
Insitebuilders Tutorial

Repeat the above steps to make a half block (8,8)

Assemble the wall (with these tools)
  1. Drag out intersecting Chalklines (Tape Measure tool)
  2. Select a corner and snap into place (Move tool)
  3. Select an axis and rotate (Rotate tool)
Insitebuilders Tutorial  

Adding detail 
It gets a little more complicated if you want to add more detail. For example, to edit the block and add hollow cells to illustrate rebar placement.: 
  1. Select the block and right click to Edit Group (or double click)
  2. Use Tape Measure tool with Ctrl to drag out chalk lines
  3. Drag out a Rectangle for the cut out
  4. Extrude the cut out down to form the hollow cell
Insitebuilders Tutorial

Here’s the model if you want to deconstruct it (InsitebuildersTut01.skp)  

Tips and Tricks
  1. Store new pieces to a warehouse file for use in future models
  2. Use the older and much simpler SketchUp v5 or v6 (download here)
  3. Stay organized with named Groups in the Outliner
  4. Use Construction Lines like you would use chalk-lines in the field.
  5. Setup Shortcut keys and Preferences as you build your model
  6. See our videos on the Insitebuilders YouTube Channel
Insitebuilders Tutorial
  1. If you get really serious, take a look at Mastering the Art of Construction Modeling.


(To be continued…)

---------------------------
The material presented in this series has been taken from our book, “How a House is Built: With 3D Construction Models” The book includes annotated illustrations, captioned text, videos, models, and the 2D Preliminaries.
Insitebuilders.com