Second and Delaware, Kansas City, MO BEST PRACTICE RECOMMENDATIONS PHIUS 1
OUTLINE VENTILATION & COMPONENT REQUIREMENTS UNDER PHIUS+ COMPARISON TO OTHER VENTILATION STANDARDS: ASHRAE 62.2 2016 ERV/HRV IRC BSC Standard 01 CONCLUSIONS & RECOMMENDATIONS 2016 Passive House Institute 2 US 2
LEARNING OBJECTIVES Understand the ventilation and system requirements for PHIUS+2015 certification as currently in place Understand components and layout requirements and best practices Understand how PHIUS+ ventilation system requirements differ from other ventilation standards Understand tech committee to be working on issuing/confirming guidance on appropriate kitchen exhaust solution 3
Definition & Purpose Controlled movement of air into and out of a building, generally using mechanical means, through deliberately placed holes in the building envelope Provide the necessary fresh(supply) air and remove the necessary stale (exhaust) air to maintain high indoor air quality (control temperature, humidity, odors, carbon dioxide, airborne contaminants, etc.) inside the building 4
Contaminants in Indoor Air From Outdoors Pollens Molds Dust CO Radon Soil gases From Indoors People Pets Formaldehydes Mold/Bacteria VOC/PM-2.5 &10 CO2 + Humidity 5
Methods for Improving Indoor Air Quality 1: Source Control Pets, harmful cleaners, bathroom/kitchen moisture & odors, airborne contaminants, offgassing building materials, etc. 2: Ventilation Bring in fresh outside air, exhaust stale inside air 3: Filtration Clean the inside air 6
Mechanical Ventilation Methods Balanced Neutral Pressure Air Inlet & Exhaust Controlled VERY Efficient w/ Heat Recovery Heat Recovery Ventilation Heating Loss is equal to 0.6-2.2 kbtu/ft²yr for cool moderate climate. This is 13-46% of the PH Heating Limit (4.75 kbtu/ft²yr) 7
Mechanical Ventilation Methods Exhaust Only Depressurizes Building Draws Air in Randomly Poor Efficiency May Hurt Building Durability Supply Only Pressurizes Building Forces Air Out Randomly Poor Efficiency May Hurt Building Durability Exhaust or Supply Only Ventilation Heating Loss is equal to 6.3-9.5 kbtu/ft²yr for Central Europe This is 133-200% of the PH Heating Limit (4.75 kbtu/ft²yr) 8
Mechanical Ventilation Heat Recovery Efficiency s. www.phius.org /Tools/Resources for: 1. HVI-Winter-Ratings-modified-for-PHIUS-modeling 9
Ventilation System Concept For Excellent Distribution ALL Ventilation Through HRV/ERV Air Extracted from Wet Rooms Supplied to Living/Sleeping Rooms 10
Ventilation Flow Criteria Supply Air: 18 cfm/person (DIN1946) OR 0.3 AC/h Typ Home: 72 cfm Max Design Airflow = Greater of Supply/ Extract Extract Air: Kitchen 35 cfm Bathrooms 24 cfm ½ Bath 12 cfm PH delivered ventilation exceeds ASHRAE 62.2, because PH sizes ventilation systems to meet actual loads, not assuming a leaky envelope will provide any fresh air 11
Ventilation System Layout - Recommendations Keep Ambient (Outside) Air Ducts Short place ventilator centrally located, close to envelope Well-Insulated w/ Vapor Impermeable Insulation Keep Conditioned (Inside) Air Ducts Within the Thermal Envelope Source: www.proairservices.i.e.com Minimize Duct Losses 12
Ventilation System Layout - Best Practice Minimize Duct Losses Smooth Interior Minimize Bends/Kinks/Constrictions Low Velocity (< 3 m/s ~600fpm) Tightly Sealed (< 3% Leakage) Size for Low & High Speed (Air Flow) Short & Centralized Duct Layout (Use Far-Throwing Diffusers & Coanda Effect) Source: www.proairservices.i.e.com Intake away from pollutant sources Intake and exhaust hoods min 6 apart, above snow levels with screened weather hoods 13
Ducts and Ventilator Noise Source: Fantech Sound Attenuation Vibration isolate ERV/HRV from floor joists Use flex duct or silencers to mitigate noise from rigid ducts between bedrooms Consider sound attenuation in walls/ceiling/floor of mechanical room 14
Ducts: Exhaust Placement Bathrooms in far corner of bathroom away from door Kitchens at least 6 away from cooktop with grease filter 15
Ducts: Supply Placement Bedrooms Living/Family Rooms Placed high in the room for coanda effect Typ. pointed towards windows Placed high in the room for coanda effect Typ. pointed towards windows Offices Dependent on occupancy For residences, treat as bedroom Conditioned Basements Supply air similar to other floors 16
Duct Layout Single Unit Example Layout Review: Find Exhaust Locations and Flow Rates Balance with Supply Locations No Short Circuits Short runs with distribution towards perimeter Duct sized properly for flow 17
Effective Ventilation System Attributes Ensure Even Distribution Throughout Balance the System (< 10% Diff.) Overflow Openings Between Rooms Use Adjustable Diffusers Set Each Register and Diffuser Balance Overall In & Out Flow Use Jump Ducts, Undercut Doors 1 Pa Maximum Differential Avoid Short Circuits No Recirculating Air Streams Controls Simple Low, Medium or High Overrides in Kitchen & Baths 18
Kitchen Ventilation Requirements 35 cfm Kitchen Exhaust Continuous Boost override in kitchen to max Recirc Hood Good capture efficiency Exhaust placement Min 6 from stove Filtration MERV 7 filter at kitchen intake 19
IAQ Measured Results Approx. continuous ventilation rate: 20+ cfm average 20
VENTILATION STANDARDS 21
ASHRAE 62.2-2016 0.01* cfm+ 0.02 cfm * per 1ft 2 (gross) + (7.5cfm x # of bedrooms +1) Example: 1,800ft 2 (gross), 3 beds (0.01cfm x 1800) + (0.02cfm x 1800) + (7.5cfm x 4) = 48cfm (mech.) + 36cfm (infiltration) = 84 cfm *ASHRAE calls for 0.03cfm/ft 2, but allows 0.02cfm/ft 2 infiltration credit 22
ASHRAE 62.2-2016 Local Exhaust Bathrooms - 50cfm intermittent / 20cfm continuous Kitchens 100cfm intermittent / has to be directly vented if rate is less than 5 ACH continuous This is a problem in medium to big and open kitchens! Example 10 Wx20 Lx9 H kitchen = 150cfm 23
ASHRAE 62.2-2016 Kitchen Exhaust Kitchens 100cfm intermittent / 5 ACH continuous Example A 10 Wx20 Lx9 H kitchen = 1800 ft3 x5ach/60min = 150cfm Workaround 1 design for intermittent (ERV/HRV on boost pulls 100cfm from kitchen) Workaround 2 define volume as reasonable area surrounding range and design for continuous Example B: 10 Wx10 Lx9 H space around range = 900 ft3 x5ach /60min = 75cfm Use booster switch and duct regulators to pull required from the kitchen 24
ASHRAE 62.2-2016 NEW Combined intake/exhaust for direct kitchen vent if cross contamination is less than 10% as attested by manufacturer in writing. NOT ALLOWED FOR BALANCED VENTILATION SYSTEMS 25
IRC 2012 and 2015 Based on square footage/bedrooms of home, s. table below 1,350ft 2 (net), 3 bedrooms = 60cfm 26
BSC Standard 01(Balanced, intermittently balanced or unbalanced) 0.01 cfm* per 1ft 2 (gross) + (7.5cfm x # of bedrooms +1) Example: 1,800ft 2 (gross), 3 beds (0.01cfm x 1800) + (7.5cfm x 4) = 48cfm *0.75 credit for balanced distributed systems: 0.75x48cfm = 36cfm 27
BSC Standard 01, additional kitchen exhaust, intermittent, directly exhausted, dampered 100 cfm per kitchen+ (7.5cfm x # of bedrooms +1) Example: 1,800ft 2 (gross), 3 beds 100 cfm x 1= 100 cfm Total ventilation for balanced distributed systems: = 36cfm + 100 cfm direct intermittent kitchen exhaust 28
Passive Buildings Ventilation Requirement, Continuous Minimum 0.30ACH (based on net enclosed volume) Example: 1,800ft 2 (gross) ~1,350ft 2 icfa Approximate volume: 1,350 x 8 = 10,800ft 3 10,800 x 0.30 / 60 = 54cfm 29
Passive Buildings Ventilation System Capacity Sizing Requirement for Max Extract Air Event (35cfm x # of kitchens) + (24cfm x # of bathrooms) + (12cfm x # powder room/laundry) Example: 1,800ft 2 (gross), 3 beds, 1 kitchen, 2 baths, 1 powder room/laundry 35cfm + (24cfm x 2) + 12 cfm = 95cfm *Assumes no infiltration to help meet requirement 30
Summary System Components Air-tight envelope, no infiltration Very efficient balanced ventilation system with heat recovery and filtration Duct system High quality recirculating range hood to capture large particles Balanced ventilation Kitchen exhaust with boost override and filter at intake Overflow provisions at rooms If direct exhaust depressurizing appliances provide make-up air If combustion appliances then directvented 31
Standard Recommendation Passive building ventilation standard: Sizing requirements, ventilation flow rates, required local exhaust Efficiency requirements by climate Testing and commissioning protocols Air-tightness and compartmentalization protocols Rules for combustion and exhaust appliances, make-up air Filtration requirements Duct system requirements, intake, exhaust placement, insulation Specify indoor air quality limits for VOC/CO2/PM 2.5-10 32
Thank You Questions? www.phius.org www.phaus.org 33