Go to Forum Home PHPP, SAP & Software Items arrising from petes list at the end of PHfest2 in mach

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    • #31206

      Here are the items I heard as current issues:

      1) clarification re floor area conventions for wardrobes and drying spaces
      2) Is both depressurisation and pressurisation necessary?
      3) Comfort condition for window surface temperatures
      4) Agreement with BRE re keeping the rules the same
      5) Issue of Translation and loosing the meaning – possibility of responding in German as well as english fro important conversations (Andrew Farr)
      6) Info sheet on appliances and nett/gross calorifica values
      7) requriemnet for a simple maual or front end for PHPP
      8) Winter Humidity investigation using welsh weather data (Alan Clarke)
      9) get all peiople onto this hidden forum ( Nick Grant) – done
      10) clarification about what k valuesa re acceptable

      Any boy want to own any of these whose not yet marked?

      Thanks for coming, pete

    • #36572
      Mark Siddall

      Can email the spreadsheet if requested (forum can not accept Excel.)

    • #36573
      Nick Grant

      What is the k value question about? Is this the BRE duct insulation requirements fiasco?

      Have enable xls and asked Tom if this is OK to do.

    • #36574
      Nick Grant

      Good point Alan I must have nodded off, real lambda values as opposed to declared is an issue. What is available/assumed in UK? Is it a mix?

      Probably not a question for PHI (clear that we use real lambda) but one for us to get hold of real lambda values for insulation. I believe evidence needs to be provided with certification?

      eg cellulose I have always used 0.04 which seems to be OK to use as real.

      Plant room seems like an anomaly. Move a wall 300mm so there is room for a coat hook and it becomes TFA. Move plant to a mezanine platform to free up precious floor area in a compact dwelling and TFA goes down. Ditto clothes drying and wardrobes, if it comes from Ikea then include as TFA, if you put doors on an alcove it comes off TFA. If you have a tumble dryer taking up 600×600 floor space then no loss of TFA . . .


    • #36575
      Mark Siddall

      BRE advise that PHI use the SAP approach to areas – mezanine excluded unless perminant stair. As you say no explicit in PHPP bible.
      Volumes another issue – noted in BRE PDF that I issued today. Warning on BRE Pressure Test Volume/V50 needs to include consealed spaces within air barrier but behind ceiling, say a dropped soffit. (Not to be confused with voids inbetween floor joists!)

      Wolfgang's text for reference:
      [# airspace within the heated part of the building using clear dimensions.
      Normally TFA * clear height of the individual room + clear volume of staircase and other parts that may not contribute to TFA. Bottom line: The clear heated air volume. Door openings/windows are disregarded.]


    • #36576

      “2) Is both depressurisation and pressurisation necessary?”
      I need to know this asap as on DE job, one passes the other doesn't – big issue for me!!!

    • #36577
      Alan Clarke

      Re Pressure test volume – as far as I am concerned this can only be the volume figure on the pressure test report – even if the tester has got it wrong that is the one to use (though at design stage you should anticipate the correct one, which I understand to be the gross volume enclosed by the airbarrier). Why? Because the pressure tester measures m3/hr not ach, and only derives the ach figure from the volume. PHPP wants m3/hr and simply multiplies the airtest ach figure by the airtest volume to get it.

    • #36578
      Nick Grant


      Not only variation in how this is done but could simply measure wrong. using their figure cancels this error out.

    • #36579
      Mark Siddall

      Re Pressure test: Surely the thing to do is to a design calc of the volume, then multiply by 0.6 and state the maximum permisable air leakage in m3/hr within the spec. This will mean that quick assessment can be made on site – otherwise have to wait for the test report, feed the data into PHPP, find it failed, phone the builder and the tester, then plug the gaps, and then call the tester out again (all that could take a few days and cause delays on site).

      (PHPP will approximate whether the leakage m3/m2 is high i.e. 0.6ach in a large building could result in 1.5 m3/m2, this is not very good for the fabric it's better to be ~0.6 m3/m2 also.)


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