Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

Buy individually or both books together. Delivery is free!


powered by Surfing Waves




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




    •  
      CommentAuthordjh
    • CommentTimeNov 6th 2014
     
    So we fitted our front door last Friday, which means the house can be closed overnight. Now I see condensation on the inside of all the locks and the inside door handles. Granted the humidity is pretty high because the plaster is still drying out so I can ventilate and heat a bit more and that will probably largely stop the condensation. But it does illustrate that both the lock and the handles are metal cold bridges through the door. Are there any ways to avoid the problem (though it may be too late for me)?
    • CommentAuthortony
    • CommentTimeNov 6th 2014
     
    No handle or lock on the outside

    Then use a plop to open the door like a car

    Why are car keys going out of fashion but house keys not?
    • CommentAuthorborpin
    • CommentTimeNov 6th 2014
     
    Posted By: djhSo we fitted our front door last Friday, which means the house can be closed overnight. Now I see condensation on the inside of all the locks and the inside door handles. Granted the humidity is pretty high because the plaster is still drying out so I can ventilate and heat a bit more and that will probably largely stop the condensation. But it does illustrate that both the lock and the handles are metal cold bridges through the door. Are there any ways to avoid the problem (though it may be too late for me)?
    Had the same problem. Be warned though, if they are the 'euro' style locks give them loads of WD40. I had 2 fail because the humidity meant they got damp inside and rusted solid!
    • CommentAuthorskyewright
    • CommentTimeNov 6th 2014 edited
     
    .
    •  
      CommentAuthorfostertom
    • CommentTimeNov 6th 2014
     
    I thought you must never oil locks cos it gunges up - graphite dust instead, in a little puffer-nozzle bottle.
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 6th 2014
     
    Our old mate JSHarris has the same problem with his locks. He pulled them apart and filled them with silicone grease.
    Don't stop the bridging though.
    • CommentAuthoralexc
    • CommentTimeNov 6th 2014 edited
     
    Car keys...
    I read the other day that electronic cars were becoming un-insurable. Lets face it, if its electronic it can be copied pretty easy. I am working at the moment making a web site logon pretty hard to beat, all i learn is be pedantic, do things the complex way.
    You may have noticed all the turmoil over leakers (snowdon et al), they have only shown that current electronic security is pretty easy to beat because the security agencies want it that way. If you do not want to change things every 2-5 years, then think it over. Faster computers (read better graphics card in parallel) will lead to quick cracks and in.

    Physical keys everywhere, imo.
    Future of computers and keys will be a usb stick with your 'key' on it, that you plug in first....sound familiar?

    sorry tony, plops are dead

    DJH: try someone like trotech for a cheap dehumidifier, our plasterer just said do it, or i think your really crazy. His partner lives next door, can't disagree as i see him too often. Works too.
  1.  
    When I was building my shed I fitted a door handle which was partially rubber coated, more from the point of view of not sticking to the handle in frosty weather, a fully coated handle would go some way to minimizing the cold bridge. There seems to be a gap in the market for thermally broken door handles or else I'm searching badly as Google doesn't seem to find any.

    I also agree that digital door locks are a bad idea, a friend has one which is also linked to their house alarm. A snooper with a wireless ip camera or just sitting across the road with a good lens could quickly get the 6 digit code needed that gets you into the house and disables the alarm. There are some which have a physical tag which you hold against the lock to open it. Seems like a step better but no doubt they can be intercepted and copied in some way too. What about the type that uses fingerprint recognition?

    The norm here in Sweden is to have all locks on the same key, even the shed etc. and it really helps in minimising the number of keys you drag around and fumbling to find the right one. But then it means re-doing all the barrels if a key gets lost.
    •  
      CommentAuthordjh
    • CommentTimeNov 7th 2014
     
    I suppose it's good to know that others have the problem and I haven't missed an obvious solution :cry:

    Thanks for the warnings about lubricating the locks. I'll research what I should be using - I'm guessing Assa will recommend something. We do have all locks on the same key, except the patio slider because it's not an Assa lock I think.

    For all the reasons everybody has mentioned, plus my own professional knowledge, there's no way I would have a digital lock on my car or house. I did see recently that there's now a device that measures your pulse. Apparently the waveform is even more unique than a fingerprint.
    • CommentAuthorDarylP
    • CommentTimeNov 7th 2014
     
    The main problem with door handles is the square section bar that links the levers inside and out.
    It has to be rigid, strong, closely toleranced.. = metal?

    Perhaps some plastic/composite structure might be better?:bigsmile:
    •  
      CommentAuthordjh
    • CommentTimeNov 7th 2014
     
    Glad I looked. Assa say:

    "Graphite is not recommended for use with cylinders, and oil should NEVER be used."

    http://www.assa.co.uk/Other/ASSACOUK/Brochure%2520PDFs/Technical/2-39%2520Info%2520For%2520Specifiers.pdf

    Needless to say, they recommend their own brand products!
    •  
      CommentAuthordjh
    • CommentTimeNov 7th 2014
     
    Posted By: DarylPPerhaps some plastic/composite structure might be better?

    Indeed. I was hoping to find that somebody knew of such a thing. But I suppose the part is put under quite a lot of stress. And one obvious candidate material - carbon fibre - is quite a good conductor of heat as well.
    •  
      CommentAuthorfostertom
    • CommentTimeNov 7th 2014 edited
     
    Posted By: alexctry someone like trotech for a cheap dehumidifier
    Make sure it's the new dessicant type, not the old compressor type. Dessicant types maintains efficiency in UK conditions; compressor types only work well in sub tropical hi temp hi humidity conditions.
    • CommentAuthorskyewright
    • CommentTimeNov 7th 2014 edited
     
    Posted By: djhIndeed. I was hoping to find that somebody knew of such a thing. But I suppose the part is put under quite a lot of stress.

    At the risk of being OT does anyone know if the square section rods are in any way "standard"? I'm going to need to replace one soon...
  2.  
    Posted By: djhGraphite is not recommended for use with cylinders, and oil should NEVER be used."
    They sell little aerosol cans of "lock oil" here for the job. Not sure how different it is from WD40.
    • CommentAuthorGreenfish
    • CommentTimeNov 7th 2014
     
    Same experiences with door handles/locks during the plaster drying phase in Feb. As Borpin says used lots of WD40 to keep the locks going. Also temporarily insulated the handles inside and out with pieces of pipe insulation, it stopped a puddle forming under the handle every morning. I am hoping it won't be a problem this winter now the house is much dryer (unless the MVHR drags in the wet air).

    A thermally broken handle would be nice wouldn't it. I have been thinking about a seasonal handle insulation fitting - pipe insukation plus... - especially on the French door that doesn't get used much in winter. Cover the outside taps, why not handles too?
    • CommentAuthorEd Davies
    • CommentTimeNov 7th 2014
     
    Posted By: Chris P BaconThere are some which have a physical tag which you hold against the lock to open it. Seems like a step better but no doubt they can be intercepted and copied in some way too.
    If they can then they're inexcusably badly engineered. There was a time when car remotes could be intercepted (and they were - there was a black market in little boxes to listen to people locking their cars and to produce the appropriate code to unlock) but now they use cryptographic techniques to stop that.

    I have to admit I'm not clear how they work - they use a long cycle of codes and when one has been used it's blocked off for a while to prevent replay attacks. What I don't understand is how that works with multiple fobs and lack of, AFAIK, two-way communication.

    A house entry system with some sort of two-way NFC should be easy to make secure with public-key cryptography. E.g., the house generates a long random number, passes it to the fob which encrypts it with its private key and sends the encrypted text back. The house then decodes it with the fob's public key, checks it's got the right number and unlocks the door.

    Bear in mind, also, that physical keys can be copied remotely. Take some nice high-resolution photographs with a long lens of somebody taking the key out of their pocket then process the image and 3D print or cut the key. It's been done at the proof-of-concept level publicly; whether it's been done black-hat is but harder to say, of course.
    • CommentAuthorborpin
    • CommentTimeNov 7th 2014
     
    Not had any troubles since I moved in. No visible condensation on the lock or handle.
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 7th 2014
     
    When I got burgled, they prised the window out. Cost £900 for a new one and all they took was a 30 quid microwave.
    Burglers are not that bothered about how they get in, more about where their next fix is coming from.
    •  
      CommentAuthordjh
    • CommentTimeNov 7th 2014
     
    Posted By: GreenfishI have been thinking about a seasonal handle insulation fitting - pipe insukation plus... - especially on the French door that doesn't get used much in winter. Cover the outside taps, why not handles too?

    Sounds like a business opportunity for different styles of cover - Christmas reindeers, pink ponies, champagne bottles. Or very expensive solar-powered trace heaters for door handles and locks perhaps?
  3.  
    Surely this amount of thermal bridging in reality is a waste of time even thinking about?
    • CommentAuthorEd Davies
    • CommentTimeNov 7th 2014 edited
     
    Suppose the cross--section of the lock is equivalent to 30 mm by 30 mm steel and the door's 50 mm thick. Steel is said to have a conductivity of 43 W/(m·K) (http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html) so the conductance of the lock is:

    >>> 43 * .03 * .03 / .05
    0.7739999999999999

    = 0.774 W/K. Over a 4000 degree-day heating season that's:

    >>> 0.774 * 4000 * 24
    74304.0

    74 kWh.

    For a pretty small Passivhaus that's 1 of your 15 kWh/m² gone.

    OK, I might be being a bit pessimistic with my assumptions but it's still worth thinking about.
    •  
      CommentAuthorjoe90
    • CommentTimeNov 7th 2014
     
    is there a low conductive material that is strong enough to take the place of the 1/4 inch square shaft used in most handles ? (nylon???)
    • CommentAuthorEd Davies
    • CommentTimeNov 7th 2014
     
    Stainless is about a quarter of the conductivity of ordinary steel

    Also, a lot less conductive of electricity, BTW: http://edavies.me.uk/2013/11/resistance-stainless/ .
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 7th 2014
     
    Nylon6, glass filled maybe.
  4.  
    Carbon fibre.....:bigsmile:
  5.  
    Posted By: Ed Davies
    Posted By: Chris P BaconThere are some which have a physical tag which you hold against the lock to open it. Seems like a step better but no doubt they can be intercepted and copied in some way too.
    If they can then they're inexcusably badly engineered. There was a time when car remotes could be intercepted (and they were - there was a black market in little boxes to listen to people locking their cars and to produce the appropriate code to unlock) but now they use cryptographic techniques to stop that.

    I have to admit I'm not clear how they work - they use a long cycle of codes and when one has been used it's blocked off for a while to prevent replay attacks. What I don't understand is how that works with multiple fobs and lack of, AFAIK, two-way communication.

    A house entry system with some sort of two-way NFC should be easy to make secure with public-key cryptography. E.g., the house generates a long random number, passes it to the fob which encrypts it with its private key and sends the encrypted text back. The house then decodes it with the fob's public key, checks it's got the right number and unlocks the door.

    Bear in mind, also, that physical keys can be copied remotely. Take some nice high-resolution photographs with a long lens of somebody taking the key out of their pocket then process the image and 3D print or cut the key. It's been done at the proof-of-concept level publicly; whether it's been done black-hat is but harder to say, of course.


    That's good to know that the fobs are a lot more secure than the ridiculous 6 digit things they are peddling here.

    As for copying physical keys all my original ASSA keys have a code etched on them that the locksmiths use to make copies.....
    • CommentAuthorHollyBush
    • CommentTimeNov 7th 2014
     
    I thought this was why many people have curtains at the back of the door, or a porch.

    Alternatively remove the square spindle thing and the catch - just use the bolt and key to lock it - the handles can be fixed handles then. (Just remember to remove the catch :-) )
    •  
      CommentAuthordjh
    • CommentTimeNov 7th 2014
     
    Posted By: HollyBushI thought this was why many people have curtains at the back of the door, or a porch.

    Traditionally, curtains are there to stop drafts. Enclosed porches also, as well as providing shelter from rain and wind. I'll grant you that a curtain would insulate the handle and lock to some degree.

    Alternatively remove the square spindle thing and the catch - just use the bolt and key to lock it - the handles can be fixed handles then. (Just remember to remove the catch :-) )

    The type of door furniture I have consists of a handle and a lock cylinder. To lock the door, lift handle to operate the (whatever the extra latches top and bottom are called) then turn the key to lock the handle and extend the deadbolt. You can't turn the key in the lock until you've lifted the handle to extend the latches. To unlock, turn the key to retract the deadbolt and free the handle then press the handle down to retract the latches.
    •  
      CommentAuthordjh
    • CommentTimeNov 7th 2014
     
    Posted By: Ed DaviesThere was a time when car remotes could be intercepted (and they were - there was a black market in little boxes to listen to people locking their cars and to produce the appropriate code to unlock) but now they use cryptographic techniques to stop that.

    As I understand it, if it's wireless it can be hacked using a man-in-the-middle attack. Two gadgets with two attackers, one near the key, simulating the car and one near the car, simulating the key. The two devices just relay the messages back and forth so the real key operates the lock remotely.

    A house entry system with some sort of two-way NFC should be easy to make secure with public-key cryptography. E.g., the house generates a long random number, passes it to the fob which encrypts it with its private key and sends the encrypted text back. The house then decodes it with the fob's public key, checks it's got the right number and unlocks the door.

    Something using physical contact rather than any form of radio and I'd agree about the theory. But there's another underlying problem with most electrical locks, which is the physical design. If you can force the lock, or access the power circuitry, then all the cryptography in the world won't help.

    Bear in mind, also, that physical keys can be copied remotely. Take some nice high-resolution photographs with a long lens of somebody taking the key out of their pocket then process the image and 3D print or cut the key. It's been done at the proof-of-concept level publicly; whether it's been done black-hat is but harder to say, of course.

    I quite like those keys that have dimples in the side rather than sawtooth edges. They're easier on the pockets, or purse, and probably harder to get useful photographs of. But it should be possible to design a scabbard that covers the key and slides back as the key is pushed into the lock, so the business end of the key is never visible.
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press