Bill of quantities

A bill of quantities (BOQ) is a document used in tendering in the construction industry in which materials, parts, and labor (and their costs) are itemized. It also (ideally) details the terms and conditions of the construction or repair contract and itemises all work to enable a contractor to price the work for which he or she is bidding.

Contents [hide] 1 Creation 2 Contingency sum 3 Criticisms 4 See also 5 References 6 Books

[edit] Creation

Bills of quantities are prepared by quantity surveyors, and “Indeed the bill of quantities was the raison d’etre for the development of quantity surveying as a separate profession.”.^[1] They are prepared by a “taking off” process in which the cost of a building or other structure is estimated from measurements in the architect's drawings. These are used to create a cost estimate such as in regard to the square area in meters of walls and roofs, the numbers of doors and windows, and systems as heating, plumbing and electrics. Similar types of work are then brought together under one item, a process known as "abstracting".

Estimating books provide the relevant costs of the materials and labour costs of the operations or trades used in construction. As the rates for materials and labour change due to inflation, these books are frequently republished.

The practice historically of estimating building costs in this way arose from non-contractual measurements, taken off drawings to assist tenderers in quoting lump sum prices.

There are different styles of bills of quantities, mainly the Elemental BOQ and Trade Bills.

[edit] Contingency sum

A Contingency sum is an item found within a Bill of quantities (BoQ).

The item refers to unforeseeable cost likely to be incurred during the contract.

There are two types of contingency sum. The first refers to a specific item i.e. 'additional alterations to services when installing said shower unit'; where an item for alterations to existing services is not contained within the BoQ but some work is envisaged.

The second type of sum is where money can be allocated to any item, within the BoQ, in the same way as the above example or used as 'additional work to be undertaken by the contractor, at the request of the contract administrator'.

The first is usually approximated by the client’s PQS and the second by the contractors QS (or commercial manager).

Additional requirements is referred as Bill of materials (BOM).

[edit] Criticisms

Bills of quantities compounds labour and material costs by combining them into a single rate that is then adjusted in regards to material quantities. They also do not consider all the main costs incurred by contractors such as construction plant, temporary works, and payments made on an interim bases in regard to work completed. Thus they do not actually model real costs. An alternative form of cost document that took account these costs was developed at Building Research Establishment called operational bills.^[2][3][4]

Bills of quantities may prevent contractors from developing effective cost control systems.^[5]

They impair transparency in regard to changes and costs “It has suggested that the reason why bills of quantity still find favour with contractors “is the opportunity it provides for creating a smoke screen around the contractor's original intentions. Thus, front end loading may go undetected, and new rates may be negotiated almost from scratch”. ^[6]

Bandwidth cap

Fire check Flush doors

Building regulation require certain doors to be able to resist the spread of fire for periods of half or one hour depending upon the sice and type of building.

Half-hour fire door (FD 30 )
A standard half hour fire door is constructed with a skeleton core to which 9.5mm thick plasterboards are fixed in rebates ins tiles and rails and over which the 3mm plywood facings are glued.

One hour fire door (FD 60 )
Flush door which are constructed to give one hour's protection have a skeleton core and 9.5mm , plasterboard infilling , with 6mm cement particle board , below the plywood facings.

Fire foor frames
These doors are hung in frames with specially deep rebates , so that fire will not easily spread around the edges of these doors.

To achieve this , they must be used in conjunction with the correct frame:

• FD 30 required a two-piece frame with a planted (nailed ) stop to form a deep rebate.
• FD 60 required a solid frame with a recess cut in the door frame to form a deep rebate.

Smoke resistance

• An effective barrier to smoke and flame is an intumescent strip fitted to the door edge or integral with the frame
• Use of intumescent strip is usually the most practical , being secured in a frame recess with a rubber-based or PVA adhesive.
• At temperature of about 150 Celcius , the seal expands to prevent passage of fire and smoke for the designated period.
• The seal will not prevent door movement for accesss and escape of personnel.
• FD 30 with two-piece frame olny required single intumescent strip
• FD 60 with solid frame required dual intumescenet strip

Fire door fittings

1. Half-hour fire doors are hung using one pair of hinges , whereas one-hour doors require one-and-a-half pairs of hinges
2. All the fire doors should have an automatic self-closing device . The door closers that are used are overhead door closers.
3. The oeverhead door closers consist of a hydraulically operated cylinder in a metal casing that is either screwed to the door face or set in a housing in the top of the door leaf for appearance sake.
4. Pivoted arms , one to the housing and one attached to the door frame , act to automatically close the door to the frame , after the door has been opened.
   

Matchboarded (battened ) doors

• Are rarely used nowadays
• These doors are made with a facing of tongued , grooved and V-jointed boards that are nailed to horizontal ledges , braces between ledges or to a frame.

Tongued , grooved V-jointed boarding

• Doors can be made out of these different structural pieces:-

-ledges , braces and battens
-Frames , ledges , braces and battens

Ledges and braced battened door

• It consists of these pieces :

-Tongued , grooved and V-jointed battens . The joints should be vertical.
-Horizontal pieces called ledges.
-Diagonal pieces called braces . Braces should be fixed so that they slope up away from the hinges.

• This is a very simple door for internal or external use.
• But the use of this type of door is limited to buildings such as sheds and outhouses and to small units such as trapdoors.
• It is cheap to make
• This types of door does not have any special woodworking joints.

Framed and braced battened door

• It consists of these pieces:

-Battens that form the surface of the door
-A frame with a head rail , bottom rail and two stiles.
-A ledge , i.e. middle rail.
-Braces.

• These doors are used for large openings to garages , factories and for entrance gates.
• This door is stronger than the ledges & braced battened door because the battens are set inside a timber frame.
• A frame and braced battened door is also more attractive than a ledges and braced battened door.
  

Raised panelled doors

• For appearance sake , entrance doors and doors to principal rooms in both domestic and public buildings are odten made more imposing and attractive by the use of panels that are raised.
• The panels are usually cut so that they are thicker at their centre than at their edges and are described as raised panels.
• Such doors are often made of hardwood , which is finishes to display the colout and grain of the wood by polish.

The usual types of raised panels are :
Bevel raised panels

• These are cut with four similar bevel faces each with a shallow rise from the edges of the panel to a point with square panels and ridge with rectangular panels.

Bevel raised and fielded panels

• These are cut with four similar bevel faces rising from the edges of the panel to a flat surface , termed the field .
• At the field , the panel is either as thick as or slightly less thick than the stiles.
• The proportion of the fielded surface to the whole panel is a matter of taste.

Raised and fielded panels

• The panels , which is of uniform thickness around the edges , is raised to a flat field at the centre with a shallow sinking.
• The field being square or rectangular depending on the shape of the panel.
• Panel may be raised on both sides or on one side olny.

Bolection moulding

• A bolection moulding is planted ( nailed ) around the panels of a door for the sake of appearance.
• The moulding is cut so that when it is fixed it covers the edges of the stiles and rails around the panel for the sake of emphasis.
• This particular section of wood moulding may be used with both raised and fieded panels on one or both sides of a door.
  

Design & construction features , advantages & disadvantages 2

• Suitable for internal and external use.
• panelled doors consist of stiles and rails framed around a panel or panels of timber or plywood.
• The stiles and rails are cut from timbers of the same thickness.
• The panels could be of solid wood , manufactured boards , glass or their combination.
• Three-ply wood 5 or 6.5mm thick is generally used for panels .
• The traditional method of fixing and securing panels in doors is to set them into the grooves cut in the edges of the stiles and rails.
• Panelled doors usually described by the number of panels that they contain .
• Because the door is hinges on the side to open , it tends to sink on the lock stile.
• The stiles and rails have to be joined to resist the tendency of the door to sink and the two types of joint used are:
  

Panelled doors terminology

Top rail - the top horizontal framing piece.
Bottom rail- the bottom horizontal framing piece.
Intermediate rail- cross pieces that divide the door into panels horizontally
Muntin-The central vertical pieces

Panels-THe folling between the framing pieces , the panels are usually fitted into rebates in the frames and screwed or nailed into place, this method allows you to remove and replace panels including glass panels , easily when required.

Design & construction features , advantages & disadvantages

• Flush doors can be faced with hardboard , plywood or plastic laminate.
• This type of door has the advantages of a plain face that is easy to clean and decorate ; it also free of the mouldings that collect dust.
• The facings of flush doors are very vulnerable to damage at the edges : therefore a lipping of solid material should be fixed to at least the vertical edges ( good -quality doors have lippings on all four edges ).
• Small glazed observation panels can be incorporated in flush doors when the glass panel is secured by loose fixing beads.

The forms of flush door construction are many and varied , but basically they can be considered as:
cellular cone flush doors

• These doors are made with a cellular core in a light softwood frame with lock and hinge blocks , covered with plywood or hardboard facings glued to the frame and core both sides.
• These lighweight doors are for light duty such as internal dosmestic doors.
• They do not withstand rough usage and provide poor acoustic privacy , security and fire resistance.
• THey are mass-produced in a small range of standard sizes and are cheap.

Skeleton core flush doors

• These doors are made with a core of small section timbers
• THe main members of this structural core are the stiles and rails , with intermediate rails , as a base for the facing of plywood or hardboard.
• The framing core members are joined with glued , tongued and grooved joints
• A flush door with a skeleton core occupying from 30 percent to 40 percent of the core of the door is a light duty door suitable for internal domestic use.
• A similar skeleton core flush door with more substantial intermediate rails in the core , where the core occupies from 50 percent to 60 percent , is a medium duty door suitable for use internally in domestic and publi buildings and for external use in sheltered positions
• This more substantial door will withstand normal use and maintain its shape stability better than a cellular core door.
• However , the facing still has a tendency to deflect betweeent he core members.

Solid core flush doors

• These doors are made with a core of timber strips glued together , with plywood facings both sides glued to the solid core.
• These doors are edges with vertical lipping to provide a neat finish
• These doors may be used as fire doors
• Because of the solid core , these doors have better shape and surface stability and acoustic resistance than the cellular or skeleton core flush door
• Their facings generally ramain flat throughtout their life.
• These doors are more expensive than cellular core or skeleton core doors.
  

Flush doors terminology

CORE

• Inner part of the door
• External boards or sheets of plywood are fixed to it.
• Can be skeleton core or solid core.

Flush Panel

• 3mm plywood or hardboard sheets which are fixed onto the core material.

Lipping

• A thin wooden strip that protects the edges of a flush door panel.

Lock Block

• A piece fitted into the internal framework of the door to make the recess for the lock.
  

Material used for doors

A door can be made of timber , glass , metal or plastic or any combination of these materials.

The doors to be considered here are those made of timber that are hung so that they swing from one edge.

Traditional timber doors are formed from solid softwood or hardwood members framed around panels.

Timber doors may be classified as:

Flush door , panelled door and Matchboarded door (battened).

Door operations

Door are supported in openings ( doorways ) on hinges as side hung , on pivots as double swing and on tracks as sliding or folding doors.

Options available include:-

Swinging

• Exterior and interior use
• Door normally turns on hinges about a side jamb when pushed or pulled , but may also be pivoted from head jamb and threshold.
• Required space around doorway for door swing ; check clearance required .
• Most convenient operation for entry and passage.
• Most effective door type for thermal and acoustic insulation and for weather resistance , can be fire-rated.

Bypass sliding

• Exterior and interior use.
• Doors slide on overhead track and along guides or a track on the floor.
• Requires no operating space but is difficult to seal against weather and sound.
• Offers access olny through 50 percent of doorway width.
• Used on exterior as sliding glass doors.
• Used in interiors primarily for visual screening.

Surface sliding

• Exterior and interior use.
• Similar to a bypass sliding door but provides access through full width of doorway.
• No operating space required but is difficult to weatherproof.
• Door is surface-hung on an exposed overhead track.

Pocket Sliding

• Interior use
• Door slides on an overhead track into and out of a recess within the within the width of a wall.
• doorway has a finished appearance when fully open.
• Often used where a normal door swings would interfere with the use of a space.

Folding

• Interior use
• Hinged door panels fold flat against one another when opened.
• Bifold doors divide into two parts , require little operating space , and are used primarily as a visual screen to enclose closet and storage spaces.
• Accordion doors are multileafed doors that are used primarily to subdivide interior spaces . They are hung from an overhead track and open by folding back in the manner of an accordion.
  

door terminology

Jamb- a solid timber or metal structure fixed to a wall . It is constructed so that it forms a seal when the door closes and supports the door's weight.
Threshold-A horizontal member at the base of an external door that separates the internal and external structure. It should slope so that rainwater dlows outside rather than inside.
Head- The horizontal piece at the top of the frame.
Jamb- The vertical part of the frame that is fixed to the wall.
Rebate- A recess in the door frame that seals the edges of a door.
Lining- The timber framework inserted into an opening in an internal wall.
Stop-A thine piece of timber fixed to the head and jambs of the lining to form a rebate.
Close stile- The outer vertical piece of the door . There are 2 types of stile: hanging stile that the door hangs on and closing stile that holds the lock or latch.
Water bar- A metal bar fitted into the threshold of an external door to prevent water flowing inside.
Weather board- A horizontal piece fixed to the external bottom edge of a door to push water away from the threshold.

Function requirement of door

Strength- a door assembly should be strong enough to sustain the conditions of use without undue damage
Stability-A door should not bow , twist or deform in normal use to the extent that its appearance is unacceptable or it is difficult to open or close.
Durability- A door should be constructed of materials that will not wear easily and required minimum amount of maintenance despite heavy use.
Fire resistance-Doors may serve two functions in the event of fire in buildings : first as a barrier to limit the spread of smoke and fire and secondly to protect escape routes.
Weather resistance- As a component part of an external wall , a door should serve to exclude wind and rain depending on the anticipated conditions of exposure.
Thermal insulation- doors , even when closed , can be a major source of heat loss and thus the resistance to heat transfer by both door and frame becomes important.
Sound Insulation- A door should afford reduction of sound for the sake of privacy and for those functions , such as tutorial rooms , where the noise level is of important.
Aestheties- Given the high level of interaction with doors and door openings , it is important that the appearance qualities o the door are considered.
Security-External doors should be designed so as to provide a secure barrier against unauthorised entry.
Privacy-Door should serve to maintain visual and acoustic privacy inside rooms to the same extent that the enclosing wallls or partitions do.

Definition , function and function requirements

A door is solid barrier that is fixed in an opening in a wall to hinge , pivot or slide open ( or to close ).

The primary function of a door when open is to allow safe means of access and egress.

Characteristics of doors which provide safe means of access and egress.

• A door opening should be sufficiently wide and high for reasonably comfortable access of people.
• Before selecting a door size , consideration should be given to the width of the corridor in which the door is to be positioned.
• Double left doors are commonly used for access to large spaces or room and for convenience in busy corridors.
• Where the door is an entrance door allowing disabled access , glazed panels should be used.

The functional requirements of doors are specified , relating to both the component parts and the whole of the door sets or assemblies (装配；程序集；集会；衣片)

How to Crack a Wi-Fi Network's WEP Password with BackTrack

You already know that if you want to lock down your Wi-Fi network, you should opt for WPA encryption because WEP is easy to crack. But did you know how easy? Take a look.

Originally published last year, we wanted to revisit Gina's awesome guide to cracking Wi-Fi WEP passwords for Evil Week. Alternatively, if you're not in a reading mood, check out the video version.

Today we're going to run down, step-by-step, how to crack a Wi-Fi network with WEP security turned on. But first, a word: Knowledge is power, but power doesn't mean you should be a jerk, or do anything illegal. Knowing how to pick a lock doesn't make you a thief. Consider this post educational, or a proof-of-concept intellectual exercise.

Dozens of tutorials on how to crack WEP are already all over the internet using this method. Seriously—Google it. This ain't what you'd call "news." But what is surprising is that someone like me, with minimal networking experience, can get this done with free software and a cheap Wi-Fi adapter. Here's how it goes.

What You'll Need

Unless you're a computer security and networking ninja, chances are you don't have all the tools on hand to get this job done. Here's what you'll need:

• A compatible wireless adapter—This is the biggest requirement. You'll need a wireless adapter that's capable of packet injection, and chances are the one in your computer is not. After consulting with my friendly neighborhood security expert, I purchased an Alfa AWUS050NH USB adapter, pictured here, and it set me back about $50 on Amazon. Update: Don't do what I did. Get the Alfa AWUS036H, not the US050NH, instead. The guy in this video below is using a $12 model he bought on Ebay (and is even selling his router of choice). There are plenty of resources on getting aircrack-compatible adapters out there.
• A BackTrack 3 Live CD. We already took you on a full screenshot tour of how to install and use BackTrack 3, the Linux Live CD that lets you do all sorts of security testing and tasks. Download yourself a copy of the CD and burn it, or load it up in VMware to get started. (I tried the BackTrack 4 pre-release, and it didn't work as well as BT3. Do yourself a favor and stick with BackTrack 3 for now.)
• A nearby WEP-enabled Wi-Fi network. The signal should be strong and ideally people are using it, connecting and disconnecting their devices from it. The more use it gets while you collect the data you need to run your crack, the better your chances of success.
• Patience with the command line. This is an ten-step process that requires typing in long, arcane commands and waiting around for your Wi-Fi card to collect data in order to crack the password. Like the doctor said to the short person, be a little patient.

Crack That WEP

To crack WEP, you'll need to launch Konsole, BackTrack's built-in command line. It's right there on the taskbar in the lower left corner, second button to the right. Now, the commands.

First run the following to get a list of your network interfaces:

airmon-ng

The only one I've got there is labeled ra0. Yours may be different; take note of the label and write it down. From here on in, substitute it in everywhere a command includes (interface).

Now, run the following four commands. See the output that I got for them in the screenshot below.


airmon-ng stop (interface)
ifconfig (interface) down
macchanger --mac 00:11:22:33:44:55 (interface)
airmon-ng start (interface)

If you don't get the same results from these commands as pictured here, most likely your network adapter won't work with this particular crack. If you do, you've successfully "faked" a new MAC address on your network interface, 00:11:22:33:44:55.

Now it's time to pick your network. Run:

airodump-ng (interface)

To see a list of wireless networks around you. When you see the one you want, hit Ctrl+C to stop the list. Highlight the row pertaining to the network of interest, and take note of two things: its BSSID and its channel (in the column labeled CH), as pictured below. Obviously the network you want to crack should have WEP encryption (in the ENC) column, not WPA or anything else.

Like I said, hit Ctrl+C to stop this listing. (I had to do this once or twice to find the network I was looking for.) Once you've got it, highlight the BSSID and copy it to your clipboard for reuse in the upcoming commands.

Now we're going to watch what's going on with that network you chose and capture that information to a file. Run:

airodump-ng -c (channel) -w (file name) --bssid (bssid) (interface)

Where (channel) is your network's channel, and (bssid) is the BSSID you just copied to clipboard. You can use the Shift+Insert key combination to paste it into the command. Enter anything descriptive for (file name). I chose "yoyo," which is the network's name I'm cracking.

You'll get output like what's in the window in the background pictured below. Leave that one be. Open a new Konsole window in the foreground, and enter this command:

aireplay-ng -1 0 -a (bssid) -h 00:11:22:33:44:55 -e (essid) (interface)

Here the ESSID is the access point's SSID name, which in my case is yoyo. What you want to get after this command is the reassuring "Association successful" message with that smiley face.

You're almost there. Now it's time for:

aireplay-ng -3 -b (bssid) -h 00:11:22:33:44:55 (interface)

Here we're creating router traffic to capture more throughput faster to speed up our crack. After a few minutes, that front window will start going crazy with read/write packets. (Also, I was unable to surf the web with the yoyo network on a separate computer while this was going on.) Here's the part where you might have to grab yourself a cup of coffee or take a walk. Basically you want to wait until enough data has been collected to run your crack. Watch the number in the "#Data" column—you want it to go above 10,000. (Pictured below it's only at 854.)

Depending on the power of your network (mine is inexplicably low at -32 in that screenshot, even though the yoyo AP was in the same room as my adapter), this process could take some time. Wait until that #Data goes over 10k, though—because the crack won't work if it doesn't. In fact, you may need more than 10k, though that seems to be a working threshold for many.

Once you've collected enough data, it's the moment of truth. Launch a third Konsole window and run the following to crack that data you've collected:

aircrack-ng -b (bssid) (file name-01.cap)

Here the filename should be whatever you entered above for (file name). You can browse to your Home directory to see it; it's the one with .cap as the extension.

If you didn't get enough data, aircrack will fail and tell you to try again with more. If it succeeds, it will look like this:

The WEP key appears next to "KEY FOUND." Drop the colons and enter it to log onto the network.

Problems Along the Way

With this article I set out to prove that cracking WEP is a relatively "easy" process for someone determined and willing to get the hardware and software going. I still think that's true, but unlike the guy in the video below, I had several difficulties along the way. In fact, you'll notice that the last screenshot up there doesn't look like the others—it's because it's not mine. Even though the AP which I was cracking was my own and in the same room as my Alfa, the power reading on the signal was always around -30, and so the data collection was very slow, and BackTrack would consistently crash before it was complete. After about half a dozen attempts (and trying BackTrack on both my Mac and PC, as a live CD and a virtual machine), I still haven't captured enough data for aircrack to decrypt the key.

So while this process is easy in theory, your mileage may vary depending on your hardware, proximity to the AP point, and the way the planets are aligned. Oh yeah, and if you're on deadline—Murphy's Law almost guarantees it won't work if you're on deadline.

---

To see the video version of these exact instructions, check out this dude's YouTube video.

Got any experience with the WEP cracking courtesy of BackTrack? What do you have to say about it? Give it up in the comments.

Gina Trapani, Lifehacker's founding editor, is tired of typing commands that start with "air." Her weekly feature, Smarterware, appears every Wednesday on Lifehacker. Subscribe to the Smarterware tag feed to get new installments in your newsreader.

Contact information for this author is not available.

Ads by Google

Industrial Wireless Solution For Harsh Environment. www.excelnex.com

Block Hacker Attacks hackers. Download GFI EventsManager www.gfi.com/block-hacker

Network Protection networks with industry experts! www.cisco.com/SBN

• Follow us to see the most popular stories among your friends -- or sign up for our daily newsletter below.

  Get Lifehacker in your inbox:
  

  Please enter your email address.

  Please enter a valid email address.

  
  
  
• 
  

By Gina Trapani

6diggsdigg

Oct 25, 2010 01:00 PM 1,612,431 386

Edit » Set to Draft » Invite » Syndicate » Edit timestamp »

Syndicate this post

Site: select site advertising consumerist deadspin defamer fleshbot gay fleshbot gawker gizmodo idolator io9 jalopnik jezebel kotaku lifehacker valleywag artists gawkershop sploid gawkertv
Mode: republish promote export

cancel

more about #wep

Crack a Wi-Fi Network's WEP Password with BackTrack, the Fancy Video Version

The Definitive Guide to Finding Free Wi-Fi

read more: #wifi, #wep, #stepbystep, #security, #homenetwork, #linux, #linuxlivecd, #livecd, #vmware, #clips, #howto, #screenshottour, #feature, #top, #smarterware, #downloads, #commandline, #evilweek