Blog Archives

How Much Hot Water Do You Need?

Posted by on 26/ 11/ 15

Most Americans use about 20 gal. of hot water a day, a standard industry benchmark. Most hot-water tanks are sized for a single day’s consumption, so an average family of four, for example, might end up with an 80-gal. tank. Solar hot-water systems should
have no trouble delivering that kind of volume, but there aren’t any safe generaliza­tions about whether it will be enough to satisfy household demands.

"The thing with hot water is that there are wide variations in demand," says Brad Collins, executive director of the American Solar Energy Society. "A 3,000-sq.-ft. house occupied by two elderly people will have substantially less demand than the exact same house next door that has five people, including two teenage girls. Their demand is tenfold what it is in the other house."

Other vari...

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Wood Flooring over Concrete

Posted by on 26/ 11/ 15

Before purchasing wood flooring for installation over concrete slabs or in sub­grade areas, check the flooring warranty to see if subgrade installations are allowed. If so, be sure to correct excess moisture conditions beforehand. In general, engi­neered wood is a better choice than solid-wood flooring in such locations because engineered wood’s cross-ply construction is more dimensionally stable. And thanks to impregnated acrylics and other factory finishes, it’s also more water resistant.

Solid-wood flooring is typically installed by first covering the concrete slab with a 6-mil polyethylene vapor barrier, spacing 2×4 sleepers on-face every 12 in. to 16 in. over the plastic, and then using power-actuated fasteners to attach the sleepers to the slab...

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Conclusion

Posted by on 26/ 11/ 15

From our earliest ancestors who created irrigation canals by scratching the ground to channel the water of a stream, to the appearance of the first technology, from the great engineering projects of Mesopotamia and China to the blossoming of the first great cities – civilization and hydraulics have always advanced hand-in-hand.

Technique, power and society

In numerous ancient civilizations, the legitimacy of those who govern – both in their own eyes and in those of the governed – rests on the social utility of their hydraulic projects. Technique and society are indissolubly linked.

Hammurabi of Babylon, conqueror of all of Mesopotamia, proclaims himself “lord of the city of Uruk” and immediately adds, as if to ensure the legitimacy of this domina­tion, that it was he who “allocated to thes...

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Guidelines for FAST Diagrams

Posted by on 26/ 11/ 15

Figure 10.1 depicts the diagramming conventions to be used in preparing a FAST dia­gram. The relative positions of functions as displayed on the diagram are also levels of activity. The FAST diagram is a horizontal graphical display based on system functions rather than system flowcharting or components. Level 1 functions, the higher-level func­tions, appear on the left side of the FAST diagram, with lower-level activity successively graphed to the right as shown. In most cases, when conducting a VE study, various levels of activity of verb-noun functions will be automatically suggested as the basic function of an item or a system.

The FAST diagram is just a tool. It is the process used in creating the diagram that is important, not the final diagram itself or its appearance...

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LAYOUT, STARTER ROWS, AND BEYOND

Posted by on 26/ 11/ 15

There are two places to install a starter row. The first and most obvious place is along a long wall. The second place is down the center of the room, which is recommended when rooms are wider than 15 ft., when rooms are complex, when several rooms converge, and when walls are out of parallel by 1 in. or more.

Flooring usually runs parallel to the length of a room, so start by measuring the width of the room at several points to see if the walls are par­allel. If the walls aren’t parallel, split the differ­ence eventually by ripping down the final row of boards on both sides of the room.

Use baseboards to conceal the expansion gaps. If baseboards aren’t thick enough to conceal the gaps, you may need to cut back the drywall as shown in "Concealing Floorboard Edges,” below.

Installing th...

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HEATING, VENTILATION, AND AIR CONDITIONING

Posted by on 26/ 11/ 15

Because HVAC system design is complex, judgement on system type, size, and location of ducts is often left to the expert – the HVAC subcontractor. But the builder should understand some basic facts to insure that the most efficient, cost-effective system available is being installed.

Select the most appropriate economical system according to home design, local climate, fuel availability, and market ^reference. If a ducted system is to be used, a concise guide is available тот the National Association of Home : Builders, 15th & M Streets, NW, Washington, DC 20005. Titled Residential Duct Systems, this guide describes the most efficient duct methods according to fuel, type of equipment, operating efficiencies, and relative cost.

Design starts with accurate heat loss calculations (and heat...

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Hand Tools

Posted by on 26/ 11/ 15

Nail guns are one of a framer’s most commonly used tools. They are also one of the most dangerous. Most framers can show you a scar from having shot themselves with a nail gun. Fortunately, many of these injuries are not serious. However, there have been instances where serious injury or death has occurred. Following are some very basic guidelines that will help you operate a nail gun safely. (Always familiarize yourself with the manufacturer’s complete operating instructions.)

• Wear safety glasses.

• Do not hold the trigger down unless you’re nailing.

• Be careful when nailing close to the edge. The push lever at the nose of the gun can catch the wood and allow the gun to fire without the nail hitting the wood, allowing the nail to fly toward whatever is in line with the gun.

• Alw...

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Interior and exterior stairs

Posted by on 26/ 11/ 15

The basic structure of the stair depends primarily on whether the stairway is to be located inside or outside and whether it is to be protected from the weather or not. The wood-stair details discussed in this chapter can be employed for either interior or exterior stair­ways, although the location will suggest basic detailing differences due to the fact that one is protected from the weather and the other isn’t.

Interior stairs—Interior stairs are usually more refined than exterior stairs. Interior stairways may be the showcase of a building and so are often located near the entry and used as a major circulation route. They may also provide the opportunity to connect more than one floor with natural light.

Exterior stairs—Exterior stairs (see 222) have the same minimum proportional r...

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Control of Compliance with an SMA Mix Recipe

Posted by on 26/ 11/ 15

14.8.3.1 determination of the Operating compliance Level

The principle of fixing frequencies of control testing depends on the number of deviations found and has been adopted in the standard EN 13108-21. With an established level of requirements (X, Y, or Z), the frequency of sampling is variable, depending on the production accuracy of the asphalt plant (i. e., the number of devia­tions from a recipe).

14.8.3.2 Start in Control

The initial frequency of sampling depends on an established category of conformity (X, Y, or Z), so at first the frequency of sampling is as follows:

• Every 150 tons of a manufactured mixture (for level X)

• Every 250 tons of a manufactured mixture (for level Y)

• Every 500 tons of a manufactured mixture (for level Z)

Samples should be representative of the...

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Floor Nailing Schedule*

Posted by on 26/ 11/ 15

Подпись: SIZE AND TYPE FLOORING SIZE NAIL TO USE SPACING T&G stripst (3/4 in. x К in., 27, in., 37, in.) 2-in. barbed flooring cleat,! 7d or 8d flooring nail, or 2-in. 15-gauge staples with 72-in. crowns! 10 in. to 12 in. apart; 8 in. to 10 in. preferred T&Gt strips (7 in. x 17 in., 2 in.) 17-in. barbed flooring cleat or 5d cut-steel or wire-casing nail 10 in. apart T&G strips (7 in. x 17 in., 2 in.) 17-in. barbed flooring cleat or 4d bright wire casing nail 8 in. apart Square-edge strips§ (5/i6 in. x 17 in., 2 in.) 1-in. 15-gauge barbed flooring brad 2 nails every 7 in. Square-edge strips§ (5/i6 in. x 17 in.) 1-in. 15-gauge barbed flooring brad 1 nail every 5 in. on alternate sides of strip Planks (4 in. to 8 in.) 2-in. barbed flooring cleat,!- 7d or 8d flooring nail, or 2-in. 15-gauge staples with 7-in. crowns! 8 in. apart Adapted, with permission, from NOFMA: The Wood Flooring Manufacturers Association, all rights reserved, © 2004. To see the chart in its entirety go to www.nofma.org/installation3.htm. Подпись: t Tongue-and-groove (T&G) flooring is blind-nailed on the tongue edge, with face-nailing required on the starting and finishing runs. t NOFMA Hardwood Flooring™ must be installed over a proper subfloor. Use 1 1/2-in. fasteners with a 3/4-in. plywood subfloor on a concrete slab. A concrete slab with sleepers every 12 in. on center does not always require a subfloor. § Square-edge flooring is face-nailed. ing or air-conditioning so indoor conditions will be close to normal (60°F to 70°F) for a week before installing flooring. Open the bundles of wood flooring and allow them to acclimate indoors for 72 hours before installing them.

Use a moisture meter to check interiors if your region has high humidity. Home centers and elec­tronics stores carry reliable, inexpensive meters. Ambient humidity indoors should be 35 percent to 55 percent; if readings are higher, consider installing a dehumidifier. Also check the moisture content (MC) of wood subfloors and flooring, using a moisture meter with probes. Typically, wood flooring’s MC is 6 percent to 10 percent.

The subfloor’s MC should not vary more than 4 percent from that of the flooring’s.

If you’re installing floors over a basement or crawl ...

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