03.04.2020  Author: admin   Cool Things To Make Out Of Wood
Thus, U. Existing permits and permit applications must be specific to the project proposed. The panel shall fixed vertically with tongue and groove joint and horizontally locked with steel bar between each other and floors and filled with cement mortar and adhesive. Insufficient support causing misalignment of duct sections Support detaching from duct assembly if attached Support deflecting under load, adversely affecting duct integrity or shape retention Support contact with duct being periodic and causing noise. Increased venous return stretches the walls of the atria pressure treated wood projects 966 specialized baroreceptors are located. Blowers may be operated pressuure or in parallel at full or reduced speed using variable frequency or voltage control.

Uncoated, polyvinyl coated, aluminum alloy coated or aluminum-zinc alloy coated steel or stainless steel may be used if a minimum corresponding base metal thickness and material strength is provided. Lockforming quality is required. The use of an alternative material requires specification or approval by a designer. Fittings shall have a wall thickness not less than that specified for longitudinal-seam straight duct in Tables and The diameter of fittings shall be appropriate for mating with sections of the straight duct, equipment, and air terminals to which they connect.

Sleeves, collars, and fittings to connect a round duct to a rectangular duct or to flexible ducts shall conform to S3. See Figures and and pages to Nothing in this specification is meant to imply that the designer cannot by project specification designate acceptable construction methods.

The use of a saddle or a direct connection of a branch into a larger duct is acceptable. Where they are used, the diameter of the branch shall not exceed two-thirds of the diameter of the main and protrusions into the interior of the main, are not allowed.

Direct connection of a branch into a main shall include mechanical attachment sufficient to maintain the integrity of the assembly. All saddle fittings shall be sealed at all pressures. Where other limitations are not stated, mitered elbows shall be based on the velocity of flow and shall be constructed to comply with Table Ducts shall be suspended in accordance with Section IV.

Additional supports shall be added if necessary to control deflection of ducts or to maintain. Round duct has a high strength to weight ratio, uses the least material to convey air at a given friction loss, and is comparatively easy to seal. The wall thickness suitable for positive pressure application is generally less than that for negative pressure. For positive pressure and low negative pressure , girth ring reinforcement is not necessary.

However, rings may be used to maintain the round shape to facilitate handling, shipment, or connection. The tables indicate that a 10" W. Some of the constructions in the tables will qualify at higher negative levels. For spiral ducts, higher negative pressure service information and bursting pressure in positive mode is available from industry sources. This manual also does not indicate preference for any one type of longitudinal seam. The length of spiral seam duct is limited by considerations such as in-line fitting frequency, potential for damage in shipment, maneuverability of the sections on the job, the number of support points needed to place the duct in its final location, and other factors.

The most popular transverse joints are the slip or lap types. The flanged joint is used in ducts over 60" mm in diameter because of its advantage in retaining the circular shape.

Access to joints for makeup and orientation in vertical or horizontal positions will influence the choice of connection. Friction loss data is provided in these design manuals. Where fittings of comparable or better performance are illustrated in duct design handbooks, designers are encouraged to consider allowing a substitution.

Omissions from this document are not intended as prohibitions against using other constructions. Double-wall rigid round duct is available from several industry sources. It is used for its acoustical value, and the perforated typically metal inner wall provides resistance to erosion of the duct liner.

Round spiral seam ducts with thinner than traditional wall thickness and with one or more corrugations ribs formed between the lock seams have been introduced in industry.

Some of these forms have been tested for compliance with UL Standard and have qualified for Class O listing.

As the industry develops more experience with these in installation and service, and as more functional performance criteria are identified, it is anticipated that such forms will be added to SMACNA construction standards. Authorities and contractors are invited to evaluate them by information currently available.

Precaution: Small differences occur in the diameter of ducts and fittings. Proper clearances are necessary. Verify suitability of fit, particularly when procurement is from outside sources. An alphabet letter in the table means that reinforcement angles or their equivalent must be used at the foot interval following the letter. The angle sizes are:. An alphabet letter in the table means that reinforcement angles or their equivalent must be used at the meter interval following the letter.

Construction of aluminum duct and fittings shall otherwise correspond in the same relationship as for steel duct. Sheet material shall be alloy H14 unless otherwise specified. Aluminum fasteners shall be used. Structural members if used shall be alloy T6 or galvanized steel as a related in table on page for rectangular duct. Hangers in contact with the duct shall be galvanized steel or aluminum. Fittings shall conform to the thickness schedules in Table , shall conform to the seam, joint, and connection arrangements permitted for round duct, and shall be Small Unique Wood Projects 50 reinforced to conform to paragraph 3.

See criteria in Section 7. Supports shall conform to those permitted for rectangular duct, with the overall dimensions taken as references. Flat oval duct combines the advantages of round duct and rectangular duct because it may fit in spaces where there is not enough room for round duct, and it can be joined using the techniques of round duct assembly.

Spiral flat oval duct is machine-made from round spiral lockseam duct and is available in varying sizes and aspect ratios. It can also be made with longitudinal seams. Flat oval duct has considerably less flat surface that is susceptible to vibration and requires less reinforcement than a corresponding size of rectangular duct. The deflection of the flat oval duct under pressure is related to the flat span rather than the overall width of the duct.

Any round duct fitting can have an equivalent fitting made in flat oval. As in rectangular duct, a hard bend elbow denotes the bend in the plane of the duct width, whereas an easy bend elbow denotes the bend in the plane of the duct height.

Any branch fitting can be made with the branch tap either round or flat oval. The tap of the flat oval fitting can be located anywhere on the circumference of the fitting body.

If the diameter of a round tap is greater than the height of the flat oval body, a transition can be made from flat oval to round, providing an equivalent area at the base of the transition. These provisions apply to ducts used for indoor comfort heating, ventilating, and air conditioning service. They do not apply to service for conveying particulates, corrosive fumes and vapors, high temperature air, corrosive or contaminated atmosphere, etc. It is presumed that project specifications define the specific materials, pressure limits, velocity limits, friction rate, thermal conductivity, acoustical ratings, and other attributes.

By UL Standard , a flexible connector is defined as a flexible air duct not having certain flame penetration, puncture, and impact tests. Bends shall be made with not less than 1 duct diameter centerline radius. Ducts should extend a few inches beyond the end of a sheet metal connection before bending.

Ducts should not be compressed. Ducts shall be located away from hot equipment such as furnaces and steam pipes to avoid excess temperature exposure. Illustrations of accessories, sleeves, and collars are representative of classes of items.

The use of components not precisely identical to these is acceptable. If the application guidelines dictated by the flexible duct manufacturer are more stringent than the specifications in this manual, those of the manufacturer shall govern. The provisions for sealing ducts specified on page apply. Adhesives shall be chemically compatible with materials they contact. Collars to which flexible duct is attached shall be a minimum of 2" 51 mm in length.

Sleeves used for joining two sections of flexible duct shall be a minimum of 4" mm in length. Collars and sleeves shall be inserted into flexible duct a minimum of 1" 25 mm before fastening. Ducts larger than 12" in mm diameter shall have at least of five 8 sheet metal screws. Non metallic flexible duct shall be secured to the sleeve or collar with a draw band. If the duct collar exceeds 12" mm in diameter the draw band must be positioned behind a bead on the metal collar.

Insulation and vapor barriers on factory-fabricated ducts shall be fitted over the core connection and shall also be secured with a draw band. These photographs depict typical accessories but do not represent all available accessories. Coincidence with proprietary features is unintentional. The standard is not intended to limit the selection or the development of accessories for use with flexible duct. A connection to another duct or to equipment is considered a support point.

Hanger or saddle material in contact with the flexible duct shall be wide enough so that it does not reduce the internal diameter of the duct when the supported section rests on the hanger or saddle material.

In no case will the material contacting the flexible duct be less than 1" wide. Narrower hanger material may be used in conjunction with a sheet metal saddle that meets this specification. To avoid tearing the vapor barrier, do not support the entire weight of the flexible duct on any one hanger during installation.

Avoid contacting the flexible duct with sharp edges of the hanger material. Damage to the vapor barrier may be repaired with approved tape.

If the internal core is penetrated, replace the flexible duct or treat the tear as a connection. Terminal devices connected by flexible duct shall be supported independently of the flexible duct.

UL, NFPA, and most codes make distinctions between these two products in their limits of application. Connectors are more restricted and are currently limited to 14" 4. Regulations governing these forms of duct should be checked especially for floor penetrations, ceiling air plenums, and fire rated floor-ceiling or roof-ceiling assemblies. These installation provisions were prepared for round ducts; however, they may also be usable for flexible flat oval ducts.

Some types of flexible duct have received listings as components of fan unit or air terminal unit systems, and they may be governed independently by the conditions of those listings. The most common metallic duct is aluminum; however, galvanized steel and stainless steel varieties are available. Nonmetal ducts are available in a wide variety of materials and nominal shape-retaining reinforcements. Machines for producing the ducts are available from several suppliers.

Flexible ducts may come to the installer in compressed form in a variety of lengths. Their length can be determined by a measurement taken with a 25 lb. Repeated flexure of metallic ducts will probably result in fatigue stress cracking.

Sections S3. Compressing duct increases first cost and friction loss. The minimum length refers to the practical route between connection points but not to the degree that the material is overstressed or to the degree that all available stretch is removed. This installation standard is applicable to ducts placed in or beneath concrete floors or in areas free from vehicle traffic. Materials commonly used for this application include galvanized steel, vinyl chloride-coated steel, and stainless steel.

Glass fiber-reinforced resin, asbestos, cement, tile, and other nonmetal ducts are also used. Ducts are not generally deemed to be or required to be waterproof.

Ducts should always be above the water table. The designer should carefully evaluate the exposure to moisture or ground water and require vapor barriers, sumps, porous fill, and subsoil drainage pipe as necessary.

CSI Specification provides useful references for subsoil drainage. The top of drain tile should be below the bottom of the duct. Corrosion resistance is an important characteristic of both in-slab and under-slab ducts. The Portland Cement Association has guidelines for protection of metals in contact with concrete.

The strength of round ducts makes them the preferred shape for underground application. Round duct wall thicknesses in these standards are generally acceptable for below-grade installation. Ribbed or corrugated styles have additional crushing strength.

Temporary internal supports can be appropriate at times. Ducts should have continuous bedding. Ducts to be embedded in concrete are subject to floating and they must be restrained.

The first pour should be the base support for the duct and anchors should be included. Twelve gage 2. Ducts buried in sand or pea gravel are not known to float. Porous fill and earth fill should not be dumped directly on ducts in trenches.

Fill should be firmly but not heavily tamped under and around the duct. The first foot of fill should be shovelled on top of the duct. Fill should not contain stones larger than 2" 51 mm. Rigid round, rectangular, and flat oval metal ducts shall be installed with support systems indicated in Tables to and Figures to They shall be installed as required to maintain alignment. Horizontal ducts shall have a support within two feet 0. Upper attachments to structures shall have an allowable load not more than one-fourth of the failure proof test load but are not limited to the specific methods shown here.

The duct hanging system is composed of three elements, the upper attachment to the building, the hanger itself, and the lower attachment to the duct. Concrete inserts must be installed before the concrete is poured. They are used primarily where the duct layout is simple and there is enough lead time to determine accurate placement. The simplest insert is a piece of bent flat bar. Manufactured inserts are available individually or in long lengths; the latter are generally used where many hangers will be installed in a small area, or where individual inserts cannot be precisely spotted at the time of placing the concrete.

Concrete fasteners are installed after the concrete has been poured and the forms have been removed. There are several variations of powder-actuated fasteners, which are placed by an explosive charge. These fasteners should not be used in certain lightweight aggregate concretes, or in slabs less than 4 inches mm thick.

Expanding concrete anchors should be made of steel. Nonferrous anchors tend to creep with vibration. Holes for expanding fasteners are drilled either by a carbide bit or by teeth on the fastener itself.

The expansion nail is a lighter duty fastener. Powder-actuated fasteners are popular for smaller ducts. Several types of beam clamps are available.

Some should be used with a retaining clip. Powder-actuated fasteners may also be used on steel. Welded studs may be installed using special welding equipment. Certain manufactured devices that are driven onto the flange will support either a rod or a band type hanger. Many office buildings are now built with a cellular steel deck that carries the electrical and communication systems and is covered with concrete fill.

The wiring in the cells and the concrete above the deck preclude the use of fasteners, such as sheet metal screws, that must pierce the deck.

Some manufacturers of this type of deck now offer an integral hanging system. In cases where there are no integral hangers at the required hanging points, install the rod or strap hangers before concrete placement, or install welded studsafter concrete placement. In all cases, the upper attachments to the decking should be in place before the application of fireproofing materials.

Upper attachment methods should be selected with care. A safety factor of 4 or 5 based on ultimate failure is practical unless it can be shown that few unpredictable variables exist and that quality control is disciplined.

Hangers are usually strips of galvanized steel or round steel rod. For hangers made of round steel rod, use uncoated hot-rolled steel except where the installation is in a corrosive atmosphere. Where corrosion is a problem, hanger rods should be electro-galvanized, all-thread rods or hot-dipped galvanized rods with their threads painted after installation.

The lower attachment is the connection between the hanger and the duct section. Fasteners that penetrate the duct may be sheet metal screws, blind rivets, or self-tapping metal screws. A straight duct section is actually a box section beam of considerable strength. As in many structures, the joint is the weakest point, so that is where the support is.

Duct joints, however, are normally strong enough to permit maximum hanger spacing at 8 2. Very wide ducts require closer hanger spacing in order to limit individual hanger loads to safe values. They also require intermediate hangers to prevent the upper portion of the duct from sagging. Trapeze members must be selected with careful attention to the position of the loads on the horizontal bar.

Load analysis is discussed in the notes for Figures and Rectangular risers should be supported by angles or channels secured to the sides of the duct with welds, bolts, sheet metal screws, or blind rivets. Here again, for ducts over 30 inches mm wide, caution must be used in fastening the support to the sheet because the expansion of the sheet due to internal pressures will tend to tear the fasteners out.

Riser support intervals should be at one or two story intervals, i. Another method is to support the riser by its reinforcing. The load can be transferred to the riser support by angles or by rods. The selection of a hanging system should not Wood Projects Hunting Near Me be taken lightly not only because it involves a significant portion of the erection labor, but also because an inadequate hanging system can be disastrous. In any multiple hanger system, the failure of one hanger transfers that its load to adjacent hangers.

If one of these fails, an even greater load is transferred to the next. The result is a cascading failure in which an entire run of duct might fall. There are many hanger alternatives, especially in the upper attachments. Figures in this manual show typical hanger constructions. See pages to for support of flexible duct.

The supports discussed here are not seismicly qualified. See Fig. See Table for rod and strap load limits. Among the deliberations that designers should consider in the selection of louvers, rooftop ducts, curbs, ventilators, supports, and other components are the following. Information on air flow pressure loss standard stock sizes, strength, corrosion, comparative cost and much other data on perforated metals is available from the Industrial Perforators Association.

Some perforated metals have the appearance of wire mesh screens. Similar data for bird screen, insect screen and other meshes for wire cloth is available from the American Wire Cloth Institute and its members. Each installation of a roof-mounted HVAC unit or roof-supported duct involves customized design requirements.

The construction details and recommendations here are therefore advisory and depend on contract documents for clarification. Openings in roofs require coordination of the architectural, structural, mechanical, and electrical contract drawings.

The height of equipment and ducts above the roof level may be influenced by snow loading, snow drifting, and wind loading as well as esthetic considerations. Designers must specify constructions appropriate for the specific locality and circumstances.

All ducts that are not watertight through the use of welded constructions or protective shields and are exposed directly to weather and solar radiation should have secure, watertight mechanical connections and receive exterior duct sealant treatment as defined in Section 1.

If exposed to direct sunlight it should also be ultraviolet ray- and ozone-resistant or should, after curing, be painted with a compatible coating that provides these plus weather resistance. The term sealant is not limited to materials of adhesive or mastic nature, but is inclusive of tapes and combinations of woven fabric strips and mastics.

Asphalt-based compounds should not be used for sealing ducts. Duct systems should not be pressurized until the sealant has had time to cure. Unless otherwise prescribed by the HVAC equipment manufacturer, ducts should be flanged for attachment to equipment with mechanical fastening plus exterior duct sealant.

Typical connections are shown in Figure The attachment method should accommodate disconnection if this is required for routine maintenance of the equipment. Where vibration isolation material is required at the connection of ducts to equipment, such material should be impervious to water. Ducts should be supported to avoid the transfer of duct weight across flexible connections. Roof penetrations by ducts should have curbs. Ducts that are interrupted at the curb should overhang the top of the curb or be flashed to divert water over the curb.

Ducts that are continuous through the curb should have flashing that slopes over the curb and is sealed to the duct with caulking or a suitable tape. Adequate clearances between ducts and roof penetration openings should be provided.

Curbs may be supplied with rooftop units or provided independently. The equipment manufacturer may outline flashing methods, structural opening requirements, sealing techniques, etc. With considerable pitch in the roof, a subbase may be required to adapt to a pre-engineered curb. Furthermore, curb mountings may incorporate vibration isolation features. All penetrations into ducts should be watertight. Duct reinforcements and supports attached to the duct should have external sealant at points of penetrations.

Attach supports with a minimum number of duct penetrations. Horizontal ducts should be pitched and provided with drainage outlets as illustrated by the system designer. If airtight, waterproof flexible insulation jackets are applied on positive pressure ducts, the installation should accommodate some duct leakage; ducts are not completely airtight.

Supports for ducts should be as indicated in Figure 5. If the support does not rest on a cap-flashed curb, the penetration of the roof membrane should have base flashing and umbrella flashing. Pitch pockets require periodic maintenance and are not permanently watertight. They are not recommended. Designers should carefully consider the proximity of intakes to exhausts and the possibility of drawing in contaminated air. The direction and elevation of discharges may be controlled by codes or standards such as NFPAM, 90A, 91, 96, or Unless details are shown otherwise on contract drawings, provide casings and plenums of the designated pressure classification as required by this standard.

Submit details selected from the illustrated alternatives for approval of the contracting authority. When equivalent construction is proposed as substitution, clearly identify the substitution. Use construction appropriate for the pressure classification.

Casing on fan discharge shall be of the designated pressure class. All joints, seams, connections, and abutments to the building structure shall be sealed with suitable compounds or gaskets. Pipe penetrations shall be sealed to prevent air leakage and condensation movement through the seal.

Casing material shall be of the same commercial grades as for ducts except that G90 coated galvanized steel shall be used in all chambers with moisture present. Close-off or safing sheets and strips shall be of G90 galvanized steel of thickness not less than that of the duct widths and shall be securely attached. They shall not be used for structural support of equipment. Casings should be built in a rectangular box shape. Tapered sides and roofs should be avoided primarily because of the difficulty in developing adequate strength and air tightness at the joints.

In theory, the tapered casings conserve energy and facilitate uniform air distribution. However, as a practical matter, the tapers required for ideal expansion or contraction are such that there is seldom enough space to accommodate them in typical equipment rooms. Several alternative constructions are illustrated. The contractor is obligated to select and use these construction details or their equivalent to satisfy the pressure level designated by the designer.

Therefore, all details such as bracing, curb connections, roof and sidewall connections, access doors, etc. Single wall casings may be constructed from continuous standing seam reinforced panels or one of the alternative constructions. The same gage of metal is used on all sides. Galvanized steel is standard sheet material. Black iron stiffeners are standard. Double-wall, factory- or shop-insulated casings are fabricated in a variety of types and thicknesses by specialized producers.

Some offer acoustical control through a perforated inner liner. There are so many possible variations of the double-wall casing construction that it is impractical to detail them in this manual. If a contractor wants to fabricate this type of casing, it is suggested that strength of the panels be determined by structural calculations or pressure tests on mock-ups.

Particular attention should be given to the design of airtight joints for panels with perforated liners. A cubic foot On one square foot 0. The following table relates static pressure to pounds per square foot:. Casings are normally set on a 4 to 6 inch high to mm concrete curb to facilitate housekeeping and also to contain any water which may leak from the coils or eliminators. The concrete curbs are normally poured on top of the finished floor. In order to prevent the forces on the casing walls from shearing off the curb, the curb should be securely doweled to the floor.

If the floor is waterproofed, the curb should be doweled through the waterproof membrane into the structural slab. Unless required to permit replacement of larger equipment such as a fan motor, duct access door size should be limited to approximately 20 inches mm wide by 54 inches mm high.

This is an adequate size for personnel and most equipment. Larger doors should be avoided since they break the continuity of the wall reinforcing.

This arrangement utilizes the air pressure rather than the door latches to force the door against the sealing gasket. All joints, seams, and connections should be sealed.

Sealing is equally important on suction and discharge sides of the fan. Gasketing may suffice for some assemblies. Leakage testing of casing is not routinely practical.

Attention to workmanship and inspection of the pressurized installation will normally suffice for airtightness. Drainage facilities must be provided in the coil and eliminator sections of the casing to handle condensation on the cooling coil. Conventional drains without deep seal traps will not give satisfactory performance. Drainage may be directly into the sewer system through a floor drain in the casing, or indirectly through the casing curb to an exterior floor drain.

If space is available, water and steam coil connections should be manifolded inside the casing to minimize the number of penetrations through the casing walls. Piping penetrations must be carefully sealed, especially on chilled water piping because any leakage will force condensation along the pipe insulation.

The casing up to the suction side of the fan is normally constructed as a conventional low-pressure casing. If the fan and the return and fresh air damper controls are not properly synchronized, it is possible that the high velocity supply fans will exert an extreme negative static pressure on the low pressure casings. It is not necessary to build these casings to withstand these unusual pressures. However, the fan and damper controls must be carefully coordinated so that it is impossible for such a negative pressure condition to occur.

Safety relief panels or dampers may be designed into the system to prevent damage. SMACNA has conducted testing and analysis of galvanized steel ducts of gages up to 96" in size, between 28 0. Tests were conducted in both positive and negative pressure modes. The study recorded pressure, deflection, and other duct element behavior.

It concluded that the structural behavior of duct is reasonably predictable in terms of pressure, deflection, metal thickness, and stiffener spacing. Committees conclude that the functional criteria previously used are valid with some new provisions for tolerances.

The general performance criteria for ducts is reviewed on page and outlined in 7. The sheet must resist both deflection caused by internal pressure and vibration due to turbulent air flow. Because space is a limiting factor, and there is a need to maintain an approximately rectangular cross section, sheet deflections for ducts were limited as listed in Figure The current test program did not include vibration analysis.

A discussion of vibration parameters follows in this chapter. Commentary also appears with Table and in the notes for Tables to It was concluded that the limited risk of an occasional problem is preferable to postponing use of multiple sheet gages until the boundaries of stability can be completely defined. Crossbreaking or beading of unbraced duct sides larger than certain dimensions is effective in dealing with commercial tolerances on out-of-flatness, natural sag from dead weight, and with the flexure reversals that may result when duct pressure is inadequate to stretch the sheet taut.

If pressure does not produce a taut sheet, vibration may result. Beading is considered as effective as crossbreaking, but formation of a suitable bead requires adjustment for each sheet thickness.

Criteria for crossbreaking or beading is given in Figure The provisions for flexure control do not eliminate rumble during start-up and shutdown. Lagging or other measures must be designed if rumble is to be eliminated.

The reinforcing members must restrain the deflection of the sheet and must resist their own deflection. They must also handle bending moments so that allowable stresses are not exceeded. Longitudinal seams must be able to withstand 1. Transverse joints must be able to withstand 1.

Where a transverse joint acts as a reinforcing member, it must not deflect excessively nor incur excessive stress. A duct section between adjacent hangers must be able to carry its own weight and to resist external loads for which it is constructed.

The joints and sheets listed in the current construction tables are not specifically designed to support the weight of a person. The support systems are not qualified for supplemental loads either. See Table and the discussion of leakage in relation to pressure level. Ducts are not absolutely airtight and designers should not impose unreasonably low limits of leakage.

Careful selection of closure methods can ensure adequate performance. However, designers must consider that even slight leakage may cause bulges in an airtight, flexible skin that encloses a positive pressure duct. Leakage is primarily a function of the static pressure differential. It is independent of joint orientation and of velocity levels of fpm Rectangular longitudinal seam leakage for Pittsburgh and snaplock seams is low compared to that in transverse joints.

Because the tables are derived from test data averages, construction conforming to Tables to will not always limit deflections of sheets and stiffeners to the stated levels. Also, crossbreaks establish an initial deflection which, when added to that generated by pressure, may result in sheet deflections slightly more than the limits discussed.

Furthermore, the ability of a reinforcing member to perform its function is critically affected by the location and adequacy of its attachment to the duct. These variables change with the negative pressure and positive pressure modes. In Easy Cheap Wood Projects Canada fulfilling this function, the duct assembly must perform satisfactorily with regard to certain fundamental performance characteristics. As the wood begins to dry, it will shrink across the fibers considerably, but very little shrinkage will occur along the length of the boards.

With this fact in mind, when you buy pressure-treated lumber, you won't have time to wait for it to dry before you buy it to see what boards warp and twist and which boards stay straight.

Instead, you'll need to find another way to judge what boards to buy. Inspect the long edges of the boards, looking for blemishes or weak spots that may show a tendency for the board to bend around the defect. Additionally, inspect the end grain of the wood. If possible, select wood whose grain lines cross the narrowest span of the end of the board. Boards that have arc-shaped end grain will likely cup more easily than boards whose end grain crosses the narrow span of the board.

When building a deck or outdoor project that calls for pressure-treated lumber to be installed with gaps between the wood, you'll likely want to install each board butted against the next board as tightly as possible. When the wood begins to the process of shrinkage as it begins to dry, the gaps will appear between the boards automatically.

Additionally, to help resist cupping, position any boards with end grain in the shape of an arc so that the center of the arc-shaped grain is pointing away from the adjoining member. So, if you're installing decking onto a framework, the center of the arc on the end grain should point upwards. Be sure to place at least one deck screw through the center of the board to help minimize the bowing as the board dries. Pre-drilling the boards before driving the screws will help maintain the integrity of the wet wood as you drive the screws.

This is a estimate proforma compiled using DSR, generated in dbSoft Hence, the users of this file are advised to verify the correctness of the data with original DSR and Correction Please drop an e-mail to me at rambabujalli gmail.

Rate is over corresponding basic item for depth upto 1. Measurements to be taken of the face area timbered. Measurements to be taken of the face area timbered :. Face area of timber permanently left to be measured. Face area of the timber permanently left to be measured.

Pipe Sleeve 50 mm dia mm long in the Bollard and M. Pipes 40 mm dia and mm long with xx6mm M. Note for item No. SR Code 4. The depth of centre of gravity shall be reckoned correct to 0. Note : Sand and aggregate shall be derived from natural sources. Uniform blending with cement is to be ensured in accordance with clauses 5.

Note: The above item shall be used judiciously where 1. Uniform blending with cement to be ensured in accordance with clauses 5. System shall consist of metal profiles with a universal aluminum base member designed to accommodate various project conditions and finish floor treatments. The Self - centering arrangement shall exhibit circular sphere ends that lock and slide inside the corresponding aluminum extrusion cavity to allow freedom of movement and flexure in all directions including vertical displacement.

Provision of Moisture Barrier Membrane in the Joint System to have watertight joint is mandatory requirement all as per the manufactures design and as approved by Engineer -in- Charge. Material shall confirm to ASTM The Joint System shall utilize light weight aluminum profiles exhibiting minimal exposed aluminum surfaces mechanically snap locking the multicellular to facilitate movement. The joints shall be of extruded aluminum base members with, self aligning and self centering arragement support plates asper ASTM B System shall consist of metal profile that incorporates a universal aluminum base member designed to accommodate various project conditions and roof treatments.

The Self centering arrangement shall exhibit circular sphere ends that lock and slide inside the corresponding aluminum extrusion cavity to allow freedom of movement and flexure in all directions including vertical displacement.

The Joint System shall resists damage or deterioration from the impact of falling ice, exposure to UV, airborne contaminants and occasional foot traffic from maintenance personnel.

Provision of Moisture Barrier Membrane in the Joint System to have water tight joint is mandatory requirement. The frame shall be measured in running metre correct to two places of decimal. Reinforcement shall be measured and paid separately. Note:- Cement content considered in this item is Kg. NOTE :- The quantity will be calculated by multiplying 1. The rate includes providing and placing in position 2 Nos 6 mm dia M. Gypsum blocks will have a minimum compressive strength of 9.

The payment of RCC band and reinforcement shall be made for seperately. NOTE:-The quantity will be calculated by multiplying the depth measured from sub-soil water level upto the centre of gravity of stone work under sub-water with the quantity of stone work in cum executed under the sub- soil water. To be secured to the backing and the sides by means of cramps and pins which shallbe paid for separately.

The steel frame work, stainless steel cramps and pins etc. The frame work shall be fixed to the wall with the help of M. Only structural steel frame work shall be measured for the purpose of payment, stainless steel cramps shall be paid for separately and nothing extra shall be paid.

Base frame work for ACP cladding is payable under the relevant aluminium items. However, for the purpose of payment, only the actual area on the external face of the curtain wall with Aluminum Composite Panel Cladding including width of groove shall be measured in sqm. Work 9. Note:- Butt hinges and necessary screws shall be paid separately.

Panelling for panelled or panelled and glazed shutters 25 mm to 40 mm thick :. Area of opening for glass panes excluding portion inside rebate shall be measured. Shutter area to be measured. Piano hinges IS : marked with necessary screws. Pipe 20 mm dia. Flat 10 cm long fixed to pelmet with hollock wood cleats of size mm x 40 mm x 40 mm on both inner side of pelmet and rawl plugs 75 mm long etc. Safety chain with 1.

The boards are to be fixed to the frame work with joints staggered to avoid through cracks, Galvanised M. Bright Bar 1. I wire on existing support complete as per direction of Engineer-in-charge. The hinge side vertical of the frames reinforced by galvanized M. The styles and rails mitred and joint at the corners by means of M.

The styles of the shutter reinforced by inserting galvanised M. The panels filled vertically and tie bar at two places by inserting horizontally 6 mm galvanised M. For W. PVC foam end cap of size 23x10 mm are provided on both vertical edges to ensure the overall thickness of 25 mm.

Core of the door shutter should be filled with High Density Polyurethane foam. Stickers indicating the locations of hardware will be pasted at appropriate places. The door frame to be fixed to the wall using M. Top, bottom and lock rails shall be provided both side of the panel.

The laminate shall be moulded with fire resistant grade unsaturated polyester resin and chopped mat. Door frame laminate shall be 2 mm thick and shall be filled with suitable wooden block in all the three legs. The frame shall be covered with fiber glass from all sides. The styles and rails shall be reinforced with M.

Solid PVC extruded bidding push fit type will be set inside the styles and the rails with a cavity, to receive single piece extruded 5 mm PVC sheet as panel. Panelling for panelled or panelled and glazed shutters 25 mm to 40 mm thick.

The FRP Chajja should be manufactured using 1. Note - Only plan area of chajjas shall be measured for making payment. With ISI marked stainless steel butt hinges of required 1.

The frame is fitted with intumuscent fire seal strip of size 10x4 mm minimum alround the frame and fixing with dash fastener of approved size and make, including applying a coat of approved brand fire resistant primer etc. The maximum glazing size shall not be more than x mm w x h or 2. Frame work shall be paid for separately. The door frame to be fixed to the wall using 8xmm long anchor fasteners complete, all as per manufacturer's specification and direction of Engineer -in- charge.

Single piece extruded 5mm thick solid PVC lock rail of size mm X 35mm out of which 75mm to be flat and 20mm to be tapered at both ends having 15mm solid core in middle of rail section integrally extruded, fixing the styles and rails with the help of solvent and self driven self tapping screws of mm X 11mm including providing 5mm single piece solid PVC extruded sheet inserted in the door as panel, all complete as per manufacturer's specification and direction of Engineer- in-Charge.

Providing with PVC snapfit beads and panel of size mm x 20 mm, and inserting 2 nos tie bar of 6 mm dia and fastening with nuts and washers complete, all as per manufacturer's specification and direction of Engineer- in-charge. Styles, rails and reinforcements to be fusion welded together.

I fasteners x 8 mm size for fixing frame to finished wall, plastic packers, plastic caps and necessary stainless steel screws etc. Variation in profile dimension in higher side shall be accepted but no extra payment on this account shall be made. Area of window upto 0. Area of window above 0. Area of window upto 2. Area of window above 1.

S friction hinges x 19 x 1. Area of window above 3. Profile of frame shall be mitred cut and fusion welded at all corners, mullion if required shall be also fusion welded including drilling of holes for fixing hardware's and drainage of water etc. Area upto 0. I fasteners x 8 mm size for fixing frame to finished wall and necessary stainless steel screws, etc. Area of door upto 2. I fasteners x 8 mm size for fixing frame to finished wall and necessary stainless steel screws etc.

Area of window upto 1. S wire mesh Two nos. Area of window above 2. Area of window above 4. Area of door above 2. Area of door above 8. Area of door above 5. Panelling for panelled and glazed shutters 25mm to 40mm thick: Pre-laminated with decorative lamination on both side exterior Grade - I MDF Board 12 mm thick confirming to IS The frame will have a provision of G.

Anchor fastners 1. The frame shall be finished with a approved fire resistant primer or Powder coating of not less than 30 micron in desired shade as per the directions of Engineer - in- charge. Cost of SS ball bearing hinges is excluded. Linear measurement of frame shall be measured for payment. Work : Sub-Head : Steel Work Sheet, joints mitred, welded and grinded finish, with profiles of required size, including fixing of necessary butt hinges and screws and applying a priming coat of approved steel primer.

Clamp shall be made of 12 mm dia M. Wire gauze with 0. This includes cost of cement slurry, but excluding the cost of nosing of steps etc.

The glass mosaic tiles shall be fixed on the wall surface with the help of approved adhesive applied at the rate of 2. All completed as per direction of Engineer-in-charge. Pedestal etc. Base plate of size mm x mm x 3mm at the bottom of the pedestal tube, G. The pedestals shall be fixed to the subfloor base through base plate using epoxy based adhesive of approved make or the machine screw with rawl plug. Access Floor panel shall be steel welded construction with an enclosed bottom pan with uniform pattern of 64 hemispherical cones.

The top and bottom plates of Steel Gauges: top 0. The panel should be Corroresist epoxy coated for lifetime rust protection and cavity formed by the top and bottom plate is filled with Pyrogrip noncombustible Portland cementitious core mixed with lightweight foaming compound.

The access floor shall be factory finished with Anti-static High Pressure laminate with Non Warp technology upto 1mm thickness for superior adhesion and Surface flatness within 0. The panel is to withstand a Concentrated Load of kgs applied on area 25mm x 25mm without collapse in the centre of the panel which is placed on four steel blocks.

All specification must be printed on the side of the panel to ensure the quality of the product. Pipe 1.

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