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1 OSite
planning
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- How suitable is
the site for a passivehouse
- Does the site have
access and utilities connections?
- Is planning permission
for a passivehouse likely?
- Is a compact building
shape possible? Terraced houses or larger blocks are an advantage.
- Is a southerly
orientation (±30°) and large south-facing window areas possible?
- Consider shading
factors preventing the use of solar gains - any trees with conservation
orders?
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2
OPre-planning
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- Compact buildings
- possible to extend existing buildings to get fewer external walls?
- Dimension south-facing
glazing for solar gains. Dimension east/north/west facing glazing for
sufficient light, not larger than necessary.
- Minimise winter
shading:
- garden walls
- vegetation
- balconies
- roof overhangs
- outbuildings.
- Simple envelope
shape, if possible avoid steps in walls, dormer windows, etc. Clearly
define the thermal (heated) envelope and the airtight layer.
- Floor plans:
- make installation
zone(s) compact and concentrated, e.g. by placing bathrooms above
or next to kitchens, etc.
- consider routing
of, and space for, ventilation ducts.
- Separate cold
basement if present:
- airtight
- no cold bridges.
- Acquire local
climate data in a form suitable for use with PHPP. Verify if calculated
by Meteonorm or similar interpolation software.
- Carry out the
first iterations of PHPP to see if the ideas add up in passivehouse
terms.
- Contact local Planning
Office to discuss initial ideas and site plan. Explain passivehouse
ventilation principles since these may not follow local regulations
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3
OPlanning
towards passivehouse realisation
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- Plan wall/foundation/roof
construction and insulation thickness.
- Avoid cold bridges
in the design - modify as required. Mitigate by minimising or optimising
cold bridging if avoidance is impossible.
- Plan in enough
space for building technology. Make sure there is space and access for
regular maintenance.
- Floor plans:
- short pipe
lengths for cold, hot and waste water
- short ventilation
ducts - cold air ducts outside the heated envelope, warm ducts inside
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4
OPlanning:
building elements
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- Ultra-insulated
construction elements according to passivehouse rules, for external
elements the rule is U ≤ 0.15 W/(m²K) - strive for 0.1 W/(m²K).
Use "Details for Passive Houses" (Springer Verlag, ISBN 978-3-211-29763-6)
as a guide (available through Amazon).
- Design connection
details to eliminate cold bridging - if in doubt calculate and verify.
- Design connection
details to assure airtightness.
- Optimise glazing:
- type of glazing
- frames/casings
- glass area
- sun shading,
etc.
- Optimise glazing:
- Calculate the
specific space heating demand using PHPP.
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5
OPlanning:
ventilation
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- Routing of ventilation
ducts:
- keep cold ducts
outside the heated envelope. If they need to be inside then only
for very short lengths and highly insulated
- keep warm ducts
inside the heated envelope. If they need to be outside then only
for very short lengths and highly insulated
- use short ducts
with smooth walls
- keep flow velocities
below 3 m/s throughout
- design measurement
and flow balancing facilities into the system
- consider fire
protection
- consider noise
factors, including noise reduction.
- Air inlets:
- avoid short-circuiting
air flows
- consider throw
widths
- incorporate
flow regulation/balancing possibilities.
- Air exhausts:
- do not place
above heating elements (if present).
- Dimension overflow
openings for a pressure drop Δp ≤ 1 Pa.
- Central ventilation/heat
recovery unit:
- position heat
exchangers close to or inside the thermal envelope. Good positions
are inside the heated envelope or in a basement
- position air
heating units inside the thermal envelope
- add additional
insulation as required in each case
- the unit should
meet or (preferably) exceed these data:
- overall efficiency
≥ 75%
- leakage to surrounding
air < 3% of the rated flow volume
- internal leakage
(between intake and exhaust air flows) < 3% of the rated flow volume
- high electrical
efficiency, power consumption < 0.45 Wh/m³ air
- have suitable
regulation/control facilities
- low noise rating
- excellent heat
insulation.
- Ventilation user
controls:
- settings: high,
normal, low
- possibly time-limited
booster functions in kitchens, toilets and bathrooms.
- Kitchen extractors
connected to the ventilation system should have good extraction capabilities
at a very low flow rate and be fitted with grease filters. However,
it is preferable to use circulation only extractors with active coal
and grease filters.
- Optionally, consider
installing a ground heat exchanger to keep intake air frost free. This
can either be a ground-to-air exchanger or a ground-to-liquid exchanger
with a liquid-to-air exchanger close to the ventilation unit. In some
climates this will probably not be required. If required, consider:
- airtightness
- distance between
cold channels and the building
- summer bypass/cooling
facilities
- extraction
of condensate
- cleaning
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6
ODesigning
additional building technology
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- Sanitation, hot
water:
- short pipes,
very well insulated
- routed inside
the thermal envelope.
- Sanitation, cold
water:
- short pipes,
normal insulation.
- Insulate warm water
and heating fittings.
- Use water-saving
taps, etc.
- Connect washing
machines and dish washers to the hot water supply.
- Waste water:
- short branch
pipes, preferably a single (internal) discharge stack
- preferably,
the stack should be ventilated into a roof void, otherwise through
an insulated external pipe.
- Sanitation
and electrical/communications installations should preferably not
penetrate the airtight layer but be cast into the foundation and
sealed. In case the airtight layer has to be breached an efficient
seal must be ensured (sleeves, tape, sealant).
- Use energy
efficient appliances, the most modern models. The inventory should
be sensible vis-a-vis PHPP
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7
OConstruction
phase - envelope
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- Site management:
Check that all materials supplied actually correspond to the materials
specifications. Run a clean site with minimal waste.
- Freedom from
cold bridges. On-site quality control.
- Integrity of
the insulation. Unbroken insulation layers - no gaps in insulation
materials.
- Airtightness:
Check transitions, e.g. between walls and floors, seals where pipes,
cables or flues are carried through the airtight layer and seams that
form part of the airtight layer while still accessible.
- Airtightness:
Carry out a pressure test as early in the construction phase as possible!
- When?
As soon as the airtight envelope is finished and while it is still
accessible, i.e. before fixes (coordinate with relevant trades).
- How?
n50-test using a blower door or the ventilation system. All leaks
must be located while the building is pressurised (smoke, handheld
anemometer, if necessary, thermography).
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8
OConstruction
phase - ventilation
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- Airtightness.
Check that piping and duct-work conserve the integrity of the airtight
envelope.
- ducts: make
sure they are clean and leak free
- central ventilation
unit: check accessibility for filter change and noise reduction
measures
- check duct
insulation - is it present where required and correctly installed?
- Flow settings in
normal operation:
- measure intake
and exhaust air flows - compare them to ensure they are balanced
- compare fresh
and stale air distribution
- measure electrical
power consumption
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9
OConstruction
phase, after fixes - additional building technology
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- Airtightness:
ensure that airtightness is preserved when installations are carried
through the airtight layer. Consider wall constructions incorporating
an internal installation void.
- Heat insulation
of pipes and fixtures: check correctness and integrity.
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10
OInduction
of owners and tenants
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- User manual:
binder with user instructions, technical manuals for equipment, warranties
and contact details for service and maintenance functions
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11
OCertification
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- Apply for a Quality-Assured
Passivehouse certificate from the Passivehouse Institute or their
UK representatives
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