1. X472 HVAC System Design Considerations
Class 6 – Specialty Systems
Todd Gottshall, PE
Western Allied
Redwood City, CA
Reinhard Seidl, PE
Taylor Engineering
Alameda, CA
Fall 2015
Mark Hydeman, PE
Continual
San Francisco, CA
2. 2
General
Contact Information
Reinhard: rseidl@taylor-engineering.com
Mark: mhydeman@continual.net
Todd: tgottshall@westernallied.com
Text
• None
Slides
• download from web before class
• Log in to Box at https://app.box.com/login
• Username: x472student@gmail.com
• Password: x472_student (case sensitive)
3. 3
Course Outline
Date Class Topic Teacher
9/03/2014 1. Introduction / Systems Overview / walkthrough RS
9/10/2014 2. Generation Systems TG
9/17/2014 3. Distribution Systems RS
9/24/2014 4. Central Plants TG
10/01/2014 5. System Selection 1 - Class Exercises RS
10/08/2014 6. Specialty Building types (High rise, Lab, Hospital,
Data center)
TG
10/15/2014 7. System Selection 2 - class exercises RS
10/22/2014 8. Construction codes and Project delivery methods TG
10/29/2014 9. 2013 T24 and LEED v4 MH
11/05/2014 10. Life-Cycle Cost Analysis RS
There are four instructors for this class. Todd Gottshall (TG), Reinhard Seidl (RS)
and Mark Hydeman (MH). The schedule below shows what topics will be covered by
who, and in what order.
4. 4
Birds Eye View of Specialty Systems
Clean Rooms
Laboratories
Kitchens
Medical Office Buildings/OSHPD
High Rise
5. 5
Birds Eye View of Specialty Systems
Too much material to go into detail on
each of the building types and systems,
but provides a “bird’s eye” overview of
what is special about represented
systems, and what to watch out for to
provide a starting point for further
detailed study
6. 6
Birds Eye View of Specialty Systems
Clean Rooms
Laboratories
Kitchens
Medical Office Buildings/OSHPD
High Rise
8. 8
Clean Rooms
Clean Room Classifications
Class
maximum particles/ft³
ISO
equivalent≥0.1 µm ≥0.2 µm ≥0.3 µm ≥0.5 µm ≥5 µm
1 35 7.5 3 1 0.007 ISO 3
10 350 75 30 10 0.07 ISO 4
100 3,500 750 300 100 0.7 ISO 5
1,000 35,000 7,500 3000 1,000 7 ISO 6
10,000 350,000 75,000 30,000 10,000 70 ISO 7
100,000 3.5×106
750,000 300,000 100,000 700 ISO 8
US FED STD 209E cleanroom standards
US FED STD 209E was officially cancelled by the General Services Administration of the US Department of Commerce
November 29, 2001,but is still widely used.
9. 9
Clean Rooms
Clean Room Classifications
Class
maximum particles/m³ FED STD 209E
equivalent≥0.1 µm ≥0.2 µm ≥0.3 µm ≥0.5 µm ≥1 µm ≥5 µm
ISO 1 10 2.37 1.02 0.35 0.083 0.0029
ISO 2 100 23.7 10.2 3.5 0.83 0.029
ISO 3 1,000 237 102 35 8.3 0.29 Class 1
ISO 4 10,000 2,370 1,020 352 83 2.9 Class 10
ISO 5 100,000 23,700 10,200 3,520 832 29 Class 100
ISO 6 1.0×106
237,000 102,000 35,200 8,320 293 Class 1,000
ISO 7 1.0×107
2.37×106
1,020,000 352,000 83,200 2,930 Class 10,000
ISO 8 1.0×108
2.37×107
1.02×107
3,520,000 832,000 29,300 Class 100,000
ISO 9 1.0×109
2.37×108
1.02×108
35,200,000 8,320,000 293,000 Room air
ISO 14644-1 cleanroom standards
10. 10
Clean Rooms
Clean Room Classifications
BS 5295 cleanroom standards
BS 5295 Class 1 also requires that the greatest particle present in any sample does not exceed 5 µm
11. 11
Clean Rooms
BS 5295:1989 identifies three states of operation similar to FS208E:
• as built - on completion, prior to moving in
• unmanned - operational but not in use
• manned - in full operational use
• Also given in the specification of Part 1 are other
requirements for cleanrooms to comply with. These are:
• minimum pressure difference between the
cleanroom and adjacent areas (see Table 4)
• filter installation test leakage
• freedom of leakage from construction joints or openings
12. 12
Clean Room Classifications
Clean Rooms
Class
maximum particles/m³
At Rest At Rest In Operation In Operation
0.5 µm 5 µm 0.5 µm 5 µm
Class A 3,520 20 3,520 20
Class B 3,520 29 352,000 2,900
Class C 352,000 2,900 3,520,000 29,000
Class D 3,520,000 29,000 n/a n/a
GMP EU classification (Good Manufacturing Practices, see also FDA website
http://www.fda.gov/Drugs/DevelopmentApprovalProcess/manufacturing/ucm169105.htm )
14. 14
Clean Rooms
Equipment choices and building layout
• Filtration is key driver, so filters are different than
in typical HVAC designs
• Remainder of equipment (AHU’s, Fans etc is
pretty “run of the mill” although sometimes
executed slightly upscale (no fan belt drives to
prevent contamination from belt shedding,
coatings, ex-proof equipment etc)
20. 20
Systems Layout
(existing tilt-up, wood roof)
Fan-powered HEPA’s
• Sometimes referred to as “MAC-10” because of the original maker’s
(Envirco) first model, but now others make fan-powered HEPA’s, too
• T24-2013 requires fractional HP fans to be ECM
21. 21
“Poor mans” cleanroom
• Class 100,000 w. retrofitted package unit
(failed particle count during rush hour next to
highway 101)
Equipment Selection
22. 22
“Poor mans” cleanroom (class 100,000)
• Retrofitted package unit (failed particle count
during rush hour next to highway 101)
Equipment Selection
24. 24
Systems Layout
(existing tilt-up, wood roof)
Example studies for project in existing building
Tilt-up , wooden roof
Building options:
• Scenario 1: Make entire building envelope leak-tight
• Scenario 2: Add equipment platform
• Scenario 3: Use modular clean room
• Scenario 4: Tunnel modules
Combined with Filter options:
• Scenario A: Non-ducted HEPA’s in pressurized supply plenum
• Scenario B: Ducted HEPA’s
• Scenario C: Fan-powered HEPA’s
25. 25
Systems Layout
(existing tilt-up, wood roof)
1A: Non-ducted HEPA’s,
sealed building
• Non-ducted outside air, return air
from chases to RAH,
• Non-ducted HEPA’s, leak-tight
supply air plenum
Advantages
• Minimal mechanical work, little
space required for mechanical
Disadvantages
• Roof (heat) load to conditioned
system to be handled by RAH
• Need to seal entire envelope incl.
roof, which may not be able to
handle weight of sheetrock or
clean room panels
26. 26
Systems Layout
(existing tilt-up, wood roof)
1B: Ducted HEPA’s, sealed
building
• Non-ducted outside air, return air
from chases to RAH,
Advantages
• Minimal mechanical work, little space
required for mechanical
• Easier supply plenum construction
Disadvantages
• Roof (heat) load to conditioned
system to be handled by RAH
• Need to seal entire envelope
incl. roof, which may not be able to
handle weight of sheetrock or
clean room panels
27. 27
Systems Layout
(existing tilt-up, wood roof)
1C: Fan powered HEPA’s,
sealed building
• Non-ducted outside air, return air
from chases to RAH,
Advantages
• Minimal mechanical work, little space
required for mechanical
• Easier supply plenum construction
• Much smaller RAH
Disadvantages
• Roof (heat) load to conditioned
system to be handled by RAH
• Need to seal entire envelope
incl. roof, which may not be
able to handle weight of sheetrock or
clean room panels
28. 28
Systems Layout
(existing tilt-up, wood roof)
2A: Non-ducted HEPA’s,
equipment platform
• Ducted outside air, ducted return
air from chases to RAH, ceiling
circulation w. exhaust fan
• Non-ducted HEPA’s, leak-tight
supply air plenum
Advantages
• Smaller overall envelope w/in
building
• No roof (heat) load to conditioned
system
Disadvantages
• Major structural work and
phasing for construction, edge
sealing
• Cost
29. 29
Systems Layout
(existing tilt-up, wood roof)
2B: Ducted HEPA’s,
equipment platform
• Equipment platform/interstitial in
building. Ducted makeup, ceiling
ventilation w. exhaust fan
Advantages
• Expandable – can add more
units, enlarge clean spaces
• No roof (heat) load to conditioned
system
Disadvantages
• Major structural work and
phasing for construction, edge
sealing
• Cost
30. 30
Systems Layout
(existing tilt-up, wood roof)
2C: Fan powered HEPA’s,
equipment platform
• Equipment platform/interstitial in
building. Ducted makeup, ceiling
ventilation w. exhaust fan
Advantages
• Expandable – can add more
units, enlarge clean spaces
• No roof (heat) load to conditioned
system
• Much smaller RAH
Disadvantages
• Major structural work and
phasing for construction,
edge sealing
• Cost
31. 31
Systems Layout
(existing tilt-up, wood roof)
3A: Non-ducted HEPA’s,
modular clean room
• Create small envelope around
clean room. Ducted makeup,
ceiling ventilation w. exhaust fan
Advantages
• Smaller overall envelope w/in
building
• No roof (heat) load to conditioned
system
Disadvantages
• Not expandable
• Double enclosure within (clean
room + discharge plenum)
within orig. envelope is
expensive
32. 32
Systems Layout
(existing tilt-up, wood roof)
3B: Ducted HEPA’s,
modular clean room
• Create small envelope around
clean room. Ducted makeup,
ceiling ventilation w. exhaust fan
Advantages
• Smaller overall envelope w/in
building
• No roof (heat) load to conditioned
system
Disadvantages
• Not expandable
• Discharge plenum easier to build,
but HEPA’s hard to
balance/access
• Support for RAH required
33. 33
Systems Layout
(existing tilt-up, wood roof)
3C: Fan-powered HEPA’s,
modular clean room
• Create small envelope around
clean room. Ducted makeup,
ceiling ventilation w. exhaust fan
Advantages
• Smaller overall envelope w/in
building
• No roof (heat) load to conditioned
system
• Much smaller RAH
Disadvantages
• Not expandable
• Discharge plenum easier to
build, HEPA’s self-balance,
less space, but more expensive
34. 34
Systems Layout
(existing tilt-up, wood roof)
4: Tunnel Module
• Ducted outside air, ducted return air
from chases to RAH, ceiling
circulation w. exhaust fan
• Non-ducted HEPA’s, leak-tight
supply air plenum
Advantages
• All components made to fit together,
price competitive
Disadvantages
• Access (Need large opening to
building)
• Lifting (need to lift AHU as one
piece)
• Needs independent structural
support
36. 36
Systems Layout
Aisle layout
Larger design - Often Clean Aisle / Dirty Aisle type layout
(much like data center hot aisle/cold aisle)
Raised floor and laminar air streamClean aisle (center), dirty aisles (grey),
“tenting” in air patterns
RAH RAH
37. 37
Clean Rooms
Pressurization / Cascading
• Typically run 0.03” – 0.05” between areas of
different cleanliness, with cleaner area at higher
pressure
• Air locks for entry/exit into cleanest areas
• Gowning protocols to prevent entry of particles
into the rooms
38. 38
Clean Rooms
Airlocks
• Nozzles inject air to
“wash” personnel
• Doors interlocked
(open door 1, remain
in airlock for x
seconds, other door
opens)
39. 39
Clean Rooms
Gowning protocol
• For high cleanliness
areas, full suit, gloves,
boots, goggles, hoods
• Means temperatures
need to be lower – full
gowning is hot
40. 40
Systems Layout
Equipment selection
Main Steps:
• Programming / room layout
• Select Required
classification
• Quantify contaminant
sources
• Decide on filter coverage
and filter face velocity (this
determines overall
recirculation airflow
• Decide on overall coverage,
or local higher classification /
local isolation
100% coverage
50% coverage
41. 41
Clean Rooms
Equipment selection
Size Recirculation AHU’s (RAH’s)
• With motor Hp of RAH’s, determine
internal loads
• Fan power of RAH’s is often just as
large or more than process loads
• Use outside air units for
dehumidification and overall building
pressurization, RAH units run non-
condensing and main design criterion
is cleanliness / related filtration airflow
requirement
• Decide on placement overhead / as
vertical vaneaxial fans, tunnel
modules, etc (many different
combinations, see earlier slides)
RA
45. 45
Clean Rooms
Equipment selection
Size Makeup units (MAU’s)
• Sufficient air for pressurization
(which is a function of the
General Contractor’s ability to
build a tight envelope)
• Sufficient air for humidity control
(where required), as a function
of diluting the humidity
generated within the space
• Resulting coil capacity added to
RAH coil capacities
• MAU often quite small
46. 46
Clean Rooms
Equipment selection
Size Makeup units (MAU’s)
• Distribute makeup air evenly
throughout plenum to various
RAH’s to prevent localized
heat/humidity effects
Makeup air
47. 47
Clean Rooms
Equipment selection
Size Recirculation AHU’s (RAH’s)
• With motor Hp of RAH’s, determine internal loads
• Fan power of RAH’s is often just as large or more
than process loads
• Use outside air units for dehumidification and
overall building pressurization, RAH units run
non-condensing and main design criterion is
cleanliness / related filtration airflow requirement
• Decide on placement overhead / as vertical
vaneaxial fans, tunnel modules, etc (many
different combinations, see earlier slides)
48. 48
Clean Rooms
Energy Considerations
• Very large air volumes (often several hundred air
changes)
• Fan power of RAH’s is often just as large or more
than process loads
• Use outside air units for dehumidification and
overall building pressurization, RAH units run
non-condensing and main design criterion is
cleanliness / related filtration airflow requirement
• Reduce airflow to minimum that will give desired
clean room class
49. 49
Improving performance
• Many clean room systems are over-designed
(perform better than strictly required), allow for fan
speed reduction on recirculation systems
especially during low use periods
• Challenge system with contaminants at low speed
to determine how low you can go, or use active
particle counts (equivalent to T’stat for temp
control)
Clean Rooms
50. 50
Improving performance
• Many clean room systems are over-designed
(perform better than strictly required), allow for fan
speed reduction on recirculation systems
especially during low use periods
• Challenge system with contaminants at low speed
to determine how low you can go, or use active
particle counts (equivalent to T’stat for temp
control)
Clean Rooms
51. 51
Particle count test
• Just under 10% drop in filter velocity (~ airflow)
for 26% drop in fan power
• How low can we go with speed?
Clean Rooms
53. 53
Particle count test
• Just under 50% drop in filter velocity (~ airflow)
for 90% drop in fan power
Clean Rooms
54. 54
Particle count test
• Filter velocity test with velgrid
Controls change
• Turn airflow down to 50% at night
• Occupancy sensors turn units back to 100%
after hours
• Control airflow from Particle Counter like Tstat
Clean Rooms
55. 55
Birds Eye View of Specialty Systems
Clean Rooms
Laboratories
Kitchens
Medical Office Buildings/OSHPD
High Rise
58. 58
Laboratories
VAV Hood control methods
Face velocity monitor
• Through-the-hood sensing (hot wire anemometer) mounted
at side of hood, just like room pressure sensor
Through-the wall opening
for airflow
59. 59
Laboratories
VAV Hood control methods
Face velocity monitor
• Through-the-hood sensing (hot wire anemometer) mounted
at side of hood, just like room pressure sensor
inside
hood
low
press
outside
hood hi
press
Measured temp of hot wire is indication of flow is indication of
hood dP is indication of hood face velocity
60. 60
Laboratories
VAV Hood control methods
Face velocity monitor
• Through-the-hood sensing (hot wire anemometer) mounted
at side of hood, just like room pressure sensor
• Do not need sash position to control a fume hood valve with
this type of controller – simply maintains face velocity
regardless of sash position
• However, cannot use just this controller for volume tracking
method for makeup / exhaust VAV’s (because we don’t
know air flow from hood, just face velocity)
61. 61
Laboratories
VAV Hood control methods
Sash position sensor
• Rope / pulley connected to potentiometer,
measures height of hood sash
63. 63
Laboratories
VAV Hood control methods
Sash position sensor
• Combination of face velocity sensor and sash
position sensor (which gives open hood face
area) now gives us overall hood exhaust volume
in cfm: velocity x area
• OR: use a flow sensor in exhaust (integrated into
hood exhaust valve, or stand-alone)
• Using hood exhaust cfm, volume tracking and
adaptive offset control can now be implemented
(see class 4)
66. 66
Laboratories
Code Requirements
• Check CBC section 443, CMC 505, 506, 510
• CalOSHA (http://www.dir.ca.gov/Title8/5143.html) see
Chap. 4, subchap. 7, Group 16, Article 107, par.
5143
• ANSI / AIHA Z9.5
• NFPA 45 (Fire dampers shall not be installed in
exhaust system ductwork)
• NFPA 45 sec.8.10.3.1 actually allows subducts(!)
67. 67
Laboratories
Fume hood velocities
• 100 fpm is default velocity for most systems, and
typically what hood mfg’s rate their hoods for
• CalOSHA (https://www.dir.ca.gov/title8/5154_1.html )
(1) Laboratory-type hood [U] average face velocity
of at least 100 feet per minute.
(2) [U] no employee is in the immediate area of the
hood opening, the ventilation rate may be reduced
[U] to a minimum average face velocity of 60 feet
per minute if the following conditions are met: (next
page)
68. 68
Laboratories
Field Testing and Commissioning
• ASHRAE Standard 110 used to test hoods in
actual field location
• Tests capture capability with tracer gas, released
within hood and “sniffed” by mannequin with
sensor in nose
• Tests also capture face velocity patterns in
response to sash movement
69. 69
Laboratories
Fume hood velocities
• 60 fpm allowable when
(A) The reduction in face velocity is controlled by
an automatic system which does not require
manual intervention. The automatic system shall
increase the airflow to the flow required by (c)(1)
when the hood is accessed.
(B) The laboratory-type hood has been tested at
the reduced flow rate according to [U] ASHRAE
110-1995
The tracer gas test need only be performed once per
hood.
71. 71
Laboratories
Hood Exhaust Routing
• Laboratory occupancy class in CMC is L-
occupancy. CBC defines laboratory suites which
are rated, <10ksqft, serve a single tenant
• 2010/2013 CBC 443.4.7.4 prohibits connecting
hood exhaust from different suites
• However, the L-occupancy is rarely if ever used,
and instead most architects classify labs as B-
occupancy
72. 72
Laboratories
Hood Exhaust Routing
• Manifolding multiple hoods together has the
following advantages:
Less ductwork
Diversity
Better dilution so that concentration of vapors in the
common exhaust duct remains < 25% LEL (lower
explosion limit) or 25% LFL (lower flammability limit)
much more easily
• But:
Incompatible materials may never be exhausted
together
73. 73
Laboratories
Hood Exhaust Routing
• If 25% LFL is exceeded (2013 CMC 505.1) then
ducts need to run directly to outside (soffit), or be
sprinklered. (NFPA 60 on explosion prevention,
included by reference via chapter 17)
• Sprinklers are a bad idea in ducts – heads corrode
in exhaust and go off when they shouldn’t or fail to
go off when they should
• Ducts full of water, not correctly designed, crash down
because of their weight and damage interior further
77. 77
Laboratories
Exhaust fans
Exhaust fans
• No induction
nozzles
• Works the same
(energy for inducing
air costs just as
much as moving
that air through a
typical utility set)
78. 78
Laboratories
Exhaust fans
Exhaust fans
• No induction
nozzles
• Works the same
(energy for inducing
air costs just as
much as moving
that air through a
typical utility set)
Access door for
flow sensor
79. 79
Laboratories
Exhaust fans
Exhaust fans
• No induction
nozzles
• Works the same
(energy for inducing
air costs just as
much as moving
that air through a
typical utility set)
Exhaust fan flow
sensor
80. 80
Laboratories
Exhaust fans
Exhaust fans
• No induction nozzles
• Works the same
(energy for inducing air
costs just as much as
moving that air through
a typical utility set)
• However, combining
momentum from
adjacent stacks does
work well
82. 82
OPTIMUM BALANCE
BETWEEN ENERGY &
AIR QUALITY
OPTIMUM BALANCE
BETWEEN ENERGY &
AIR QUALITY
HIGH FLOW & HIGH ENERGY
TYPICAL MANUFACTURER
SPECIFICATIONS
HIGH FLOW & HIGH ENERGY
TYPICAL MANUFACTURER
SPECIFICATIONS
LOW FLOW & LOW ENERGY
UNDER-DESIGNED
SPECIFICATIONS
LOW FLOW & LOW ENERGY
UNDER-DESIGNED
SPECIFICATIONS
“SAFE & ENERGY EFFICIENT”“SAFE & ENERGY EFFICIENT”
Adverse
Air Quality
Adverse
Air Quality
WASTED ENERGY
POTENTIAL
WASTED ENERGY
POTENTIAL
Air IntakeAir Intake
Air IntakeAir Intake
Air IntakeAir Intake
Energy vs. Air Quality
83. 83
Laboratories
Exhaust fans
Exhaust plume studies
• Plume calculation
• May lead to lower stack exit velocities than 3,000 fpm while still
maintaining safe conditions, so can save energy (much like
prescriptive vs performance path in T24)
CPP (Cermak Peterka Peterson)
84. 84
Laboratories
Fire mode
Supply fans shut down in fire
Exhaust fans cannot (hoods have to continue to
run)
• Design needs to include some kind of relief to prevent building
from becoming very negative
• Doors may not have more than 30 lbs initial / 15 lbs final door
pull force (for fire doors) and 5 lbs for non-fire doors
• See 2013 CBC 1008.1.3: 1008.1.3
• Room pressure exerts a force on doors that becomes
problematic around 0.25” or so (creates 14 lbs force on a 3’x7’
ft door with handle, or 27 lbs force on middle of door when
panic bar is used)
85. 85
Laboratories
Fire mode
Relief paths:
• In exterior (ie. backdraft damper, not easily accepted by
architects)
• Relief shaft to lab rooms
• Operable windows or doors in exterior for relief
Reduce exhaust flow:
• Close all general room exhaust, open all room supply with
bypass on roof, exhaust only through hoods
• Drop hood exhaust to 60 ft in fire with AHJ approval
• Use automatic sash closers
87. 87
Birds Eye View of Specialty Systems
Clean Rooms
Laboratories
Kitchens
Medical Office Buildings/OSHPD
High Rise
88. 88
Kitchens
• Commercial Kitchens need systems to protect the people
cooking and the buildings they are in
• Mechanical issues to be resolved:
Exhaust Smoke, Grease-laden, or steam vapors from the
cooking or cleaning process
Remove heat
Possibly provide cooling
Replace exhausted air
Fire Suppression
91. 91
Kitchens
Regulated by:
Chapter 5 Exhaust Systems of the California
Mechanical Code
http://www.iapmo.org/2013%20California%20Mechanical
%20Code/Chapter%2005.pdf
Title 24-2013 Energy Measures
http://www.energy.ca.gov/2012publications/CEC-400-
2012-004/CEC-400-2012-004-CMF-REV2.pdf
92. 92
Kitchens
• Roles and Responsibilities
Food Service (Kitchen) Designer
Designs the layout, appliances, grease or steam hood capacities, and
hood specifications
Hood Controls is usually within their scope but can be informed by the
Mechanical Engineer
Fire Suppression System
93. 93
Kitchens
• Roles and Responsibilities
Mechanical Engineer
Exhaust Duct Systems sized for loads established by Food Service
Exhaust Fans
Space Cooling/Heating Loads
Makeup Air Systems: Equipment and Distribution
Controls
Interface with Hood Exhaust Controls
Interface with Fire Suppression Systems
94. 94
Kitchens
Design Resources
• ASHRAE Handbooks
• Food Service Technology Center (The PEC for Commercial
Kitchens)
http://www.fishnick.com/
• ASHRAE Articles
95. 95
Kitchens
Hood types (Defined by ICC/IMC not
IAPMO/CMC)
• Type I Hoods: Grease Laden Exhausts
• Type II Hoods: Steam and Heat Exhausts
• Current CMC does not explain this difference and
co-mingles requirements. Very confusing.
104. 104
Kitchens
Duct Slope
• Type I requires:
¼” per Foot Slope toward Hood or Grease
Reservoir
1” per Foot slope if horizontal run is 75’ or longer
• Use Zig-Zag for long horizontal runs
105. 105
Kitchens
Duct Rating
• Exhaust Duct Enclosed in
Continuous Rated Enclosure
above lowest fire-resistive
ceiling to Roof or Shaft.
• Commonly use Fire Wrap for 2-
Hour Enclosure equivalence
and Zero Clearance to
combustibles
106. 106
Kitchens
Duct Access For Inspection and Cleaning
• Horizontally
Every change in direction
Every 12’ if less than 20”x20”
• Vertically
From Top if Person can physically inspect
Every floor of Multistory Riser if less than ~24”x24”
108. 108
Kitchens
Variable Volume Exhaust
Control the Exhaust and
Conditioned Makeup based
on Cooking Load
Sensors monitor Temperature
and Smoke in Hood. Increase
exhaust to maintain Capture
and Containment
114. 114
Kitchens
Makeup Air Sources
• Traditionally a Dedicated Makeup Air Unit with
heating and perhaps evaporative or mechanical
cooling. Electrically interlocked to GEF.
• Modern designs maximize use of transfer air (i.e.-
used Ventilation Air from Central Systems)
Relieve out the exhaust fan rather than envelope or
relief air fan
115. 115
Kitchens
Makeup/Supply Air Distribution
• Deliver air away from Hoods so as not to disturb airflow
into hood
• Displacement air to allow air to flow smoothly into hood
• Dumping Diffusers (Exhausts as Supplies) some
distance in front of hood
• Sidewalls throwing away from hood
118. 118
Kitchens
Fire Suppression and Control
• UL 300 Fire Suppressant
• Potassium Based Chemical
• AND possibly Water
• Gas Shut Off
• Turn On Exhaust Fan
• Not usually in Mechanical Scope
120. 120
Kitchens
Energy Code Requirements-2013
• Maximum Exhaust Rates for Hoods, less than the
prescriptive CFM values for Unlisted Hoods in CMC Ch. 5.
• Limits use of unlisted hoods to small kitchens
125. 125
Kitchens
Energy Conservation Measures
• Get Hood as low to the process as possible
• Use UL Listed Hoods that are engineered for
capture and containment at lower airflows
• Add side panels or increase overhang to focus
exhaust
126. 126
Birds Eye View of Specialty Systems
Clean Rooms
Laboratories
Kitchens
Medical Office Buildings/OSHPD
High Rise
127. 127
Medical Office Buildings
OSHPD (http://www.oshpd.ca.gov/)
Leader in collecting data and disseminating information about
California's healthcare infrastructure
Monitors the construction, renovation, and seismic safety of
hospitals and skilled nursing facilities
DOES NOT oversee OSHPD 3/MOB/Clinic Facilities Construction
Permitting or Inspections
133. 133
Medical Office Buildings
OSHPD inspections vs built to OSHPD
standards
• As with LEED certification, many facilities use
OSHPD rules for design but are not required to be
inspected according to OSHPD
• Be clear in understanding what the owner wants
and is required to do
134. 134
Medical Office Buildings
Zoning and Thermostat settings
• Nurse stations and moving staff always cool
settings
• Exam rooms always warm settings (people
seated, partially undressed)
• Doctor’s offices separate stats
138. 138
Medical Office Buildings
OSHPD 3 Mechanical Code (CMC) Adoptions:
CH. 4 Ventilation
1. Natural Ventilation Only Supplemental to Mechanical Ventilation
2. Outdoor Ventilation Intake
• 25’ from exhausts or similar
• 18” from Roof Surface
• 10’ from Grade
3. Exhaust Terminations
• 10’ from Grade or Window/Door
4. Relief Air Termination
• 10’ from Outdoor Air Intake
139. 139
Medical Office Buildings
OSHPD 3 Mechanical Code (CMC) Adoptions:
Space Ventilation Rates, Pressure Relationships and Filter
Requirements
CMC Ch. 4 Table 4-A CMC Ch. 4 Table 4-B
Negative (infectious) vs positive (immune
system impaired)
Filter No. 1: Upstream of Equipment
Filter No. 2 &3: Downstream of Equipment
140. 140
Medical Office Buildings
Airflow requirements
• 2013 CMC table 4-A airflow requirements –
recirculation systems vs 100% OA systems
• Example: a clean work room can be served by at
least 4 air changes per hour (ACH) from a 100%
outside air unit. OR: by 2 ventilation ACH (outside
air) out of a total of 6 ACH, so 4 ACH worth
recirculated, i.e. design for 6 ACH with 33% OSA
or 8 ACH with 25% OSA etc.
141. 141
Medical Office Buildings
OSHPD 3 Mechanical Code (CMC) Adoptions:
Transfer Air and VAV Control
• Air Transfer to Rated Corridors OK if
necessary for Pressure Relationship
• Space Above Ceiling can’t be use for
Plenum Return. ALL DUCTED
RETURN
• VAV not appropriate for some rooms
• Return and/or Exhaust needs to track
VAV Supply CFM like LAB Design
142. 142
Medical Office Buildings
To Shaker-Test or Not To Shaker-Test?
That is a Good Question
CBC Chapter 17A requires Special
Seismic Shaker-Test OSHPD 3 Facilities are
NOT required to satisfy this
requirement!
143. 143
Medical Office Buildings
Local HEPA Filter and CV Terminals, Ducted RA
ROOM # DESCRIPTION ACC.CMC
TABLE 4-A
PRESS.
TO ADJ.
MIN. AC
PER HOUR
OA/COND
ACTUAL EXHAUSTE
D
DIRECTLY
TO
OUTSIDE
ROOMS CFM SQFT ACH
PROCEDURE 2017 TREATMENT ROOM E 6 450 318 10 -
UTILITY 2018 STERILIZER EQUIPMENT
ROOM
N 10 220 (2) 154 10 YES
PROCEDURE 2019 TREATMENT ROOM E 6 270 306 6 -
SOILED UTILITY 2023 SOILED WORKROOM
(UTILITY)
N 10 150 102 10 YES
EXAM 1 2022 TREATMENT AND
EXAMINATION ROOM
E 6 90 102 6 -
OBS1/2/3 2013-2015 PATIENT ROOM E 4 350 191 13 -
NURSE STATION / CU 2011/2012 CLEAN LINEN STORAGE
(1)
P
(1)
2 550 188 20 -
OFFICE 2016 N/A N/A N/A 200 137 10 -
HALL 2020 PATIENT AREA
CORRIDOR
E 4 270 472 4 -
JANITOR 2025 JANITORS CLOSET N 10 30 (2) 18 12 YES
TOILET 2009 TOILET ROOM N 10 70 (2) 45 11 YES
TOILET 2010 TOILET ROOM N 10 80 (2) 51 11 YES
1) CLEAN UTILITY 2012 IS LOCATED IN SAME AREA AS HALL 2020, NURSE STATION 2011 AND OBSERVATION 2013-2015.
NO PRESSURE RELATIONSHIP OTHER THAN “E” CAN BE MAINTAINED
2) EXHAUST ONLY, WITH TRANSFER AIR AS MAKEUP.
144. 144
Medical Office Buildings
Local HEPA filter and CV terminals, ducted RA
Local HEPA
filter w fan
assist
Ducted RA
within
designated
OSHPD area
only
145. 145
Medical Office Buildings
Typical Hospital Equipment: MRI
• Conditioning
Typical Heating/Cooling for Room
Air or Water Cooled Glycol Chiller for MRI Magnet
• Shielding
Ducts within the RF Shield around Magnet Room – Non-Ferrous
Wave Guide Grids in Ducts at Shield Penetration
• Cryogenic Quench/Vent Pipe
Vent Pipe to roof or sidewall with 25’ clearance
Vent Pipe must be able accommodate Thermal Contraction
Supply and Return should be close via dampers on discharge.
• Noise
Ducts may need sound attenuation to adjacent spaces
http://youtu.be/9SOUJP5dFEg
146. 146
Medical Office Buildings
Main OSHPD-driven design rules
• AHU design: Final filtration stage for critical areas
downstream of all other coils, fans etc in AHU.
HEPA (MERV 17) filters for units serving
operating rooms, and 90% ASHRAE Dust Spot
(MERV 14) filters for selected treatment rooms
• 2013 CMC Table 4-B, 4-C
147. 147
Medical Office Buildings
Typical Hospital Equipment
Copper shielding
• for room essential to prevent RF
interference and magnetic fields
• At PAMF, journeyman had his
hammer pulled from his belt in
walking past the MRI room (door
open), and the hammer flew 10ft
across the room and smashed
into the MRI
• Right: copper covered wall
panels
148. 148
Medical Office Buildings
Typical Hospital Equipment
Copper shielding
• for room essential to prevent RF
interference and magnetic fields
• At PAMF, journeyman had his
hammer pulled from his belt in
walking past the MRI room (door
open), and the hammer flew 10ft
across the room and smashed
into the MRI
• Right: copper covered wall
panels
149. 149
Medical Office Buildings
Typical Hospital Equipment
Copper shielding
• Penetrations get waveguides
(much like the front of your
microwave oven) in the duct,
• All thermostats, wiring, diffusers,
duct, screws, are non-metallic
(Aluminum or SS)
150. 150
Medical Office Buildings
Typical Hospital Equipment
Cooling and Cryo vent
• MRI is typically cooled with low
temp cascade chiller system to
keep liquid Helium at liquid
stage.
• Must be connected and cooling
turned on right as MRI comes off
truck, He typically stays liquid for
4-5 days max without cooling, so
after shipping from factory, must
be connected to prevent rupture
disc blowing charge, and ship
back to factory
151. 151
Medical Office Buildings
Typical Hospital Equipment
Cooling and cryo vent
• Vent pipe runs should be
kept short – if not possible,
then they become just like
steam piping – venting of He
will contract vent pipe due to
very drastic temperature
changes, and require
compensation for contraction
153. 153
Medical Office Buildings
Typical Hospital Equipment:
Ophthalmology Equipment Vibration Isolation
Isolation Tables
Ducts/Equipment Spring Isolation
154. 154
Medical Office Buildings
Typical Hospital Equipment
• Cooling systems (non-condensing CHW for
sensitive equipment)
• Ensure that a loop is available for medium
temperature CHW (like 55F) that can be fed to
equipment which cannot handle condensation
inside the equipment (much like data center
CDU’s – 3 way valve and secondary pump)
155. 155
Birds Eye View of Specialty Systems
Clean Rooms
Laboratories
Kitchens
Medical Office Buildings/OSHPD
High Rise
157. 157
Highrise
Fire/Life Safety Systems
Fire/Life Safety Systems
• When buildings are tall enough that the local fire
department ladder trucks cannot reach the top
floor (varies by city), ~75’ Tall, ~7 Stories
• Then the building has to be equipped with a
fire/life safety system in accordance with Chapter
909 of the 2013 CBC
158. 158
Smoke control system
• Pressurization method: exhaust fire floor, pressurize
surrounding floors (with or without Supply Air) (Common)
• Airflow method: show that airflow is sufficiently large to
maintain speed across openings that prevents smoke
migration (Uncommon)
• Exhaust method (Atria, malls): provide sufficient airflow at
low velocity to keep plume intact and rising due to
temperature so that plume can be exhausted at top without
mixing with surrounding air
Highrise
Fire/Life Safety Systems
159. 159
Pressurization method
• Pressurize stairwells, pressure cascades to adjacent
vestibules. So stairwells are higher pressure than vestibules
than floors.
• Create pressure differential between fire floor and
surrounding floors
(can use air terminals, but only if controllers are UUKL listed
for use in fire/life safety controls)
Otherwise use floor-by-floor FSD’s or use large dampers
(“dump dampers”) with relays on fire alarm system
Highrise
Fire/Life Safety Systems
160. 160
Fireman’s panel
• Create template for
mounting on fireman’s
panel showing “easy to
read” status of all major
equipment and FSDs
Highrise
Fire/Life Safety Systems
161. 161
Fireman’s panel
• Create template for
mounting on fireman’s
panel showing “easy to
read” status of all major
equipment and FSDs
Highrise
Fire/Life Safety Systems
163. 163
Atrium Method
• Provide supply air to fire at less than 200 fpm to prevent
disturbing plume of smoke
• Exhaust plume at top, limit spread by rated partitions around
atrium
• Ensure that smoke stays above 6 ft high for exiting
purposes for the duration of exit requirements
Highrise
Fire/Life Safety Systems
164. 164
Atrium Method
• CFD study for smoke spread
The Fire Consultants
Highrise
Fire/Life Safety Systems
165. 165
Atrium Method
• CFD study for smoke spread (visibility Isosurfaces)
The Fire Consultants
Start of
fire
End of
exiting
period
Highrise
Fire/Life Safety Systems
167. 167
Highrise – Stack Effect
Buoyancy effect from different
temperatures inside and outside building
• Winter: Building is warm inside and cold outside –
positive pressure builds at top of building,
negative pressure at bottom (just like very large
chimney at fireplace), very high pressures can
result (large driving force: 70˚F- 5˚F = 65˚F diff.)
• Summer: reverse effect, but typically less
dramatic effect (105˚F - 75˚F = 30˚F difference)
168. 168
Highrise – Stack Effect
Buoyancy effect from different
temperatures inside and outside building
70˚F interior,
5˚F ambient
40 story ~ 550 ft
∆p = 0.018 * 14.7 * 550 * (1/529.6 – 1/464.6) = 0.04 psi
0.04 psi = 1.11” wg
169. 169
Highrise – Stack Effect
Pressure results
• 1.1” wg on a 3’x7’ elevator lobby door = 63 lbs
door force (i.e. impossible to open)
• Hard or impossible to “fight” these differentials
with HVAC equipment
• Need to provide architectural separation of worst
pressure steps
• Rotating doors at bottom of hotel lobbies are an
obvious example
171. 171
Highrise
MEP pressures
Heat exchangers to separate floors
• For piping systems in very tall buildings, prevent
extreme pressures from building up by adding
heat exchangers that separate circuits
• Loses some efficiency, but keeps components
cheaper