ASHRAE
American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc.
1791 Tullie Circle, NE • Atlanta, Georgia 30329-2305
404-636-8400 • Fax 404-321-5478
SPC/GPC MINUTES COVER SHEET
(Minutes of all SPC/GPC Meetings are to be distributed to all persons listed below within 60 days following the meeting.)
SPC/GPC NO.:
SPC/GPC TITLE:
SSPC 15
ISSUE DATE:
March 20, 2008
Safety Standard for Refrigeration Systems
DATE OF MEETING:
January 20, 2008
LOCATION: New York, NY
Attendance
Voting Members Present
Status
Others Present (con’d)
Status
Douglas T. Reindl
Phillip A. Johnson
Stephen W. Duda
Dennis R. Dorman
Danny M. Halel
Jay A. Kohler
Martin L. Timm
John I. Vucci
PCVM – Chair
PCVM – Vice-Chair
PCVM – Secretary
PCVM
PCVM
PCVM
PCVM
PCVM
Voting Members Absent
Status
Ajay R. Chatlani
PCVM
Others Present
Status
Wayne K. Borrowman
Daryl K Showalter
Masoon Ali
Kent Anderson
Bruce Badger
Jeff Berge
Don Blacklock
NVM
NVM
Guest
Guest
Guest
Guest
Guest
Tom Blewitt
Jim Crawford
Paul Doppel
Felix Flohr
Daniel GiGuere
Bruce Griffith
Rainer Grosse-Kracht
David Hinde
Umar Khokhar
Travis Lumpkin
Kirsten McNeil
Peter Narreau
John Rasch
Hermann Renz
Brian Rodgers
Scott Smith
Bob Stanford
Hidekazu Tani
Mike Thompson
Ron Vallort
Tom Watson
Gary Zyhowski
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
Guest
-1These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
DISTRIBUTION:
ALL MEMBERS OF SSPC 15
ALL ATTENDEES (ABOVE)
LIAISONS:
SPLS: Byron W Jones
Staff: Mark Weber
-2These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
Meeting Summary
Action Items (carried forward from previous Meetings):
06A-06.
Status: Complete / Closed.
07W-01.
Status: Complete / Closed
07W-02.
Responsible Party: M. Timm, C. Radcliffe, J. Kohler
Action: Further refine and develop Kohler CM Change Proposal #15-06-12-0002. Consider the
possibility that some form of containment may be required; and whether the Proposal as written could
allow the release of live steam.
Status: No significant progress since last meeting; work continues.
07W-03.
Status: Complete / Closed
07W-04.
Responsible Party: S. Duda, D. Dorman, J. Vucci, M. Timm and the Proposer
Action: Further study Domina CM Change Proposal #15-06-12-0001 to evaluate its possible merits. M.
Timm offered to run release dispersion computer models.
Status: On this Meeting’s Agenda.
07W-05.
Responsible Party: D. Halel
Action: Further study McClure CM Change Proposal #15-05-12-0004-002; solicit comments from TC
03.08, refrigerant leak detector manufacturers, and perhaps others.
Status: In progress at this meeting; work continues.
07A-01.
Responsible Party: D. Reindl.
Action: Reindl to distribute a *.pdf copy of the Standard 15-2007 for official committee use.
Due Date: Completed.
07A-02.
Responsible Party: D. Reindl.
Action: Chair will to obtain Letter Ballot from two absent members prior to the July 1, 2007 Roster for
Motions 2, 3, and 4.
Due Date: Completed.
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These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
07A-03.
Responsible Party: D. Reindl and M. Timm.
Action: Refine and complete work on Timm Change Proposal 15-07-12-0003/002 (classification of
cascades systems).
Due Date: On this Meeting’s Agenda.
07A-04.
Responsible Party: D. Reindl, S. Duda, M. Timm.
Action: With respect to Domina Change Proposal 15-06-12-0001 (Revise 15’ clause of 9.7.8), perform
PHAST modeling to confirm ground level, 20’ and 15’ refrigerant dispersion figures. Variables to be
considered include Stability Class Type C and F; quiet air and moving air; free area versus a wall or
obstruction. Request concentration in bands.
Due Date: On this Meeting’s Agenda.
07A-05.
Responsible Party: J. Kohler and D. Dorman
Action: With respect to Domina Change Proposal 15-06-12-0001 (Revise 15’ clause of 9.7.8), research
typical mass flow rates of relief discharge for outdoor air-cooled chillers, for R-134a. Consider different
relief rates; B1 refrigerants; a differentiation between large and smaller machines.
Due Date: On this Meeting’s Agenda.
07A-06.
Responsible Party: G. Zyhowski.
Action: With respect to McClure Change Proposal 15-05-12-0004-001 (removal of refrigerant vapor),
obtain some modeling-based research analysis to justify proposed resolution.
Due Date: No significant progress since last meeting; work continues.
Action Items (new this Meeting):
08W-01.
Responsible Party: Entire Committee.
Action: Review Calm Change Proposal #15-08-12-0001/001 (Materials; Pertains to Clause 9.1.5.) and be
prepared to discuss at the next Meeting.
Due Date: 2008 Annual Meeting..
SUMMARY OF MOTIONS:
-4These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
Secretary’s Note: All votes recorded herein are formatted as Aye-Nay-Abstain-Absent. Chair voted unless noted
otherwise.
1. Motion:
Second:
Text:
Vote:
2. Motion:
Second:
Text:
Vote:
3. Motion:
Second:
Text:
Vote:
S. Duda
D. Halel
Approve the SSPC 15 Meeting Minutes of June 24, 2007 (Annual Meeting in Long Beach, CA) with one
correction: Addendum identification letters should be lower case.
Motion Carried 8-0-0-1
M. Timm
E. Troy
To Approve for Publication Public Review: Reindl Change Proposal #15-07-12-0004/002 as Amended in
Attachment E.
Motion Carried 8-0-0-1 with Letter Ballot required to absent member A. Chatlani. Post-meeting
Secretary’s note: Letter Ballot to absent member was returned with a “yes” response, so Motion Passes
9-0-0-0.
D. Dorman
D. Halel
Adjourn.
Motion Carried by voice vote.
-5These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
MINUTES
I.
Call to Order / Quorum Call
a) Call to Order - Doug Reindl, Chairman, called the meeting to order at 1:06 pm EST at the Sheraton New York
Hotel, Riverside Ballroom, New York, NY. Eight Voting members (of Nine) were in attendance, thereby
constituting a quorum.
II.
Introduction of Members And Guests
a) Self-introductions of members and guests were made around the table as the attendance roster was circulated.
Reindl welcomed all guests and visitors.
III.
Approval of Long Beach June 24, 2007 Annual Meeting Minutes
a) D. Reindl offered one correction to the Long Beach June 24, 2007 Annual Meeting Minutes: Addendum
identifying letters should be lower case. S. Duda offered a MOTION to approve the Long Beach June 24, 2007
Annual Meeting Minutes as amended above. D. Halel offered a Second. Show-of-Hands Vote: Motion Carried
(8-0-0-1).
Secretary’s Note: All votes recorded herein are formatted as (Aye-Nay-Abstain-Absent); Chair voting unless
noted otherwise.
IV.
Summary of PC Chair’s Breakfast
a) Tentative new Provision to the Standards procedure: All public review comments may soon be required to be
posted electronically via the ASHRAE website database.
b) All interested parties should re-subscribe with their contact information to receive an electronic subscription to the
Standards Actions e-mail list server. The previous list was inadvertently deleted. This will give subscribers
notification of actions, such as public review drafts and addendum publication updates, for Standards in which
they have an interest. Visit http://www.ashrae.org/publications/detail/16150
V.
Roster Update
a) Gene Troy changed from Voting Member to Consultant on the Roster as of 1.16.2008.
VI.
Liaison reports (Liaisons)
a) CIS – (Phil Johnson / Daryl Showalter): 2007-08 ICC Change Cycle – several Change Proposals are related to
Standard 15 – addressed in Item XI.d) of these minutes. Recommendations are due to ASHRAE Staff in advance
of mid-February ICC Meeting.
b) Std. 34 – (Kohler): Addendum c to 2007 Edition; possible bundling of Standards 15 & 34. Reindl interjected
that this bundling has been adopted by Steve Comstock. Kohler reported that he confirmed at the on-site
bookstore that both Standards are shrink-wrapped together. Also, some discussion of the ‘B’ classification of
toxicity is taking place, for re-evaluation of its ramifications.
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These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
c) Refrigeration Committee – (Bruce Griffith): Reported some work and technical guidance for CO2 as a
refrigerant.
d) No other reports were given.
VII.
Review of Action Items from Previous Meetings (Reindl)
a) The committee reviewed each Action Item from the previous meetings. See status report included herewith.
VIII.
Standard 15-2007 Addenda (Reindl)
a) Addendum b to the 2007 Edition – Formerly known as Radcliffe Change Proposal #15-05-12-0002; has been
approved through the Public Review Process (no comments; see Attachment A); has been approved by Society
Standards Committee; and is therefore officially adopted as part of the Standard. It will be published as
Addendum B on the ASHRAE website and will be incorporated into the base text in the next publication cycle.
b) Addendum d to the 2007 Edition – Formerly known as Reindl Change Proposal #15-07-12-0003/001; has been
approved through the Public Review Process (no comments; see Attachment A); has been approved by Society
Standards Committee; and is therefore officially adopted as part of the Standard. It will be published as
Addendum D on the ASHRAE website and will be incorporated into the base text in the next publication cycle.
c) Addendum e to the 2007 Edition – Formerly known as Reindl Change Proposal #15-07-12-0003/003; has been
approved through the Public Review Process (no comments; see Attachment A); has been approved by Society
Standards Committee; and is therefore officially adopted as part of the Standard. It will be published as
Addendum E on the ASHRAE website and will be incorporated into the base text in the next publication cycle.
d) Addendum f to the 2007 Edition – Formerly known as Reindl Change Proposal #15-07-12-0004/001 has
received five (5) public review comments from three (3) commenters (found in Attachment B). Reindl came to
the meeting with a proposed draft response to each comment (discussed but not adopted). A review and
discussion of each comment was held as follows:

Commenter 0001 proposed changing the minimum equipment pressure rating of 25% above saturation
pressure at its warmest location to 10%. Halel expressed agreement in concept. Reindl, Timm, others feel
10% is too narrow (only about 6°F margin).

Commenter 0002 – proposed changing the minimum equipment pressure rating of 25% above saturation
pressure at its warmest location to 20% and adds “where liquid or saturated CO2 is likely to be present.”
SSPC 15 consensus is that 20% seems a reasonable compromise. Halel advocates the added text. Dorman
advocates no specific percentage unless we can articulate a solid reason.

Commenter 0003/001 – proposed changing the minimum equipment pressure rating of 500 psig to 400 psig.
Halel agrees (might even accept 360 psig). Reindl points out that 500 psig corresponds nearly to 32°F
ambient. Guest comments that most cascade low-temperature systems never approach these suction
pressures. General advocacy among guests who spoke are in favor of something lower than 500 psig. Timm
offered that the 500 psig was developed to avoid nuisance relief to atmosphere of CO2 on (for example)
warm-up of cold systems on power failure (but is that related to safety? Or just related to good design, for
which SSPC 15 does not have purview). Kohler reminded us that 500 psig was a significant decrease over
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These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
what the requirement would be without the original Continuous Maintenance Change Proposal. Another
suggestion is not to list any particular pressure; rather, define how to determine the pressure in each case
related to the design working pressure. No formal vote, but consensus of voting members is to remove any
specific pressure floor – Reindl will take this back to the commenter as a potential resolution.
IX.

Commenter 0003/002 – Discusses “normal” conditions – Reindl suggests this is irrelevant and beyond the
scope of the original Continuous Maintenance Change Proposal. The SSPC 15 committee generally agrees.

Commenter 0003/003 – Changes “saturation pressure at its warmest location” to “circuit pressure.” Reindl
recommends rejecting this suggestion and SSPC 15 generally agrees.

Based on the above discussion, Reindl withdrew his draft suggested responses and will forward new proposed
responses based on discussions with commenters.
CM Change Request Update
a) Kohler – 15-06-12-0002 (Relief venting for R-718) – Refer to Attachment D. Kohler provided an oral summary.
Did not make significant progress toward agreement. Item carries forward. One subcommittee member (Carl
Radcliffe) passed away – Kohler requests additional participation. ACTION ITEM #07W-02.
b) Reindl – 15-07-12-0004/002 (Hydrostatic Relief) – Reindl reported an inability to resolve public review
commenters. Refer to Attachment E for a new proposed revision, involving definitions of engineering and
administrative controls and allowing administrative controls in certain cases, such as maintenance. Discussion
about impracticality of engineering-only controls in large built-up systems. This has been a difficulty for endusers in jurisdictions where the current language is literally enforced, and by a recent OSHA interpretation. M.
Timm offered MOTION to approve for publication public review the new alternative text as found in Attachment
E. P. Johnson offered a SECOND. Discussion followed – Kohler questioned under what circumstances must one
consider temperature rise; implying that normal building a/c temperatures are not low enough to make this a
concern; Reindl replied that this is in the manufacturer’s hands for packaged equipment. Watson/Anderson also
commented similar to Reindl’s response. Vote: Motion PASSED 8-0-0-1 with letter ballot required to absent
member Chatlani. Post-meeting Secretary’s note: Letter Ballot to absent member was returned with a “yes”
response, so Motion Passes 9-0-0-0. This is now designated Addendum g and is out for Public Review from
March 21 to April 20, 2008.
c) Domina – 15-06-12-0001 (Revise 15’ clause of 9.7.8) (Duda) – Refer to Attachment F. Duda reported on work of
subcommittee as follows:

M. Timm presented the results of his dispersion modeling – see Attachment G. Initial modeling was based on
R-22 refrigerants. A guest asked about dynamic narrowing of pipe due to refrigerant frost; Timm responded
that this was not considered; steady-state was assumed. Watson asked about back-pressure dynamics. Dorman
noted that, based on Timm’s modeling, 5’ away from discharge point seems safe in most cases. Most unitary
equipment discharges at rates in the neighborhood of 20 ppm. Question as to discharge at sidewall (neither
up nor down) not covered by the model yet. Then Timm moved on to Ammonia as the refrigerant – some
discussion followed. Long discussion related to a number of specific installation conditions, and whether to
try to include all cases or simply the air-cooled outdoor equipment. SSPC 15 offered thanks and appreciation
to Timm for the modeling effort.
-8These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.

Item carries forward to the next Meeting. Duda, Vucci, Dorman, Kohler will help define further modeling.
ACTION ITEM #07W-04.
d) McClure 15-05-12-0004-001 (removal of refrigerant vapor) (G. Zyhowski): Refer to Attachment H. In process.
Zyhowski is present and reports that he intends to obtain some modeling-based research analysis. Item carries
forward to the next meeting. ACTION ITEM #07A-06.
e) McClure 15-05-12-0004-002 (refrigerant detectors) (Halel): Refer to Attachment I. Reviewed in committee. D.
Halel is meeting with refrigerant detector manufacturers following this meeting and will report. At a previous
SSPC 15 meeting, a consensus agreement was reached that specification of infrared (or any other) specific
technology is not appropriate in a Standard. The Standard can define performance and testing requirements, but
not any specific technology. It was suggested that the committee should obtain input from leak detector
manufacturers, and work is still needed in establishing performance criteria. ACTION ITEM #07W-06.
f) Calm 15-08-12-0001/001 (Materials): Pertains to Clause 9.1.5. Refer to Attachment J. Background information
is that some inspectors are not allowing PVC for refrigerant pressure relief discharge piping. Initial discussion
was held, but no formal action taken. Carry forward to next meeting. ACTION ITEM #08W-01.
X.
Interpretation Requests
a) There are no formal Interpretation Requests pending.
XI.
Update on related standards
a) IIAR-2 (Kirsten McNeil): Eight (8) comments were received in response to the Second Public Review Draft of
IIAR-2. Ventilation is a primary focus of these comments, and a ventilation machinery room task force was
appointed. A probable 3rd Public Review period will be forthcoming.
b) ISO 5149 (Kohler) Report on subcommittee meeting earlier today: 2nd committee draft was issued in April 2007;
this subcommittee participated with comments (22 pages and 119 comments) and met at least twice to discuss.
Effort continues.
c) UL (presented informally by Rodgers, Guest) 1995: UL is receiving requests for certified CO2 systems; next
meeting is in February.
d) CIS (Johnson) IBC Changes update: The ICC (International Code Council) has a number of proposed revisions to
the International Building Code (IBC). The ICC is asking SSPC 15 to comment on several relevant revision
proposals, asking if we favor, oppose, or remain neutral. A discussion was held, and Johnson will take the results
back to the ICC via CIS. For definition of each of the following discussion items, refer to Attachment K.

Regarding M24: The consensus of SSPC 15 is to Strongly Disagree with footnotes i, j; Agree with 0.50 cfm/sf
Reason: Continuous ventilation is needed for safety.

Regarding M90: The consensus of SSPC 15 is to Strongly Disagree – propose to change “be constructed in”
to match the 9.3.1.1.c “meet the requirements of . . .”

Regarding M91: The consensus of SSPC 15 is to remain Neutral.

Regarding M92: The consensus of SSPC 15 is to Disagree (Code does not apply retroactively).
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These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
XII.

Regarding M95: The consensus of SSPC 15 is to Agree.

Regarding M96: The consensus of SSPC 15 is to Disagree with 1105.7.1 and 7.2 because it is technically
incorrect; and Agree with 1105.8.

Regarding M97: The consensus of SSPC 15 is to Disagree unless ICC clarifies that “remote control” means
“emergency shutdown.”

Regarding M98: The consensus of SSPC 15 is to remain Neutral.
Other Business
a) General Advisory: Dept of Homeland Security has requirements for chemical handling screening, which apply to
some refrigerants (such as ammonia) in excess of 10,000 lbs.
b) Former committee member Carl Radcliffe passed away since the previous meeting. A moment of silence was
observed in his memory.
XIII.
Adjournment
a) Next Meeting: Sunday, June 22, 2008 at 1:00 pm MDT in Salt Lake City, UT.
b) Dorman offered a Motion to Adjourn / Halel offered a Second. Approved by voice vote. Chairman Reindl
declared the meeting adjourned at 4:57 pm local time.
End of Minutes
Respectfully submitted by:
Stephen W. Duda
Secretary of SSPC 15
March 20, 2008
- 10 These Minutes were approved by vote of this Committee on June 22, 2008 and are the official, approved record of the proceedings.
ATTACHMENT ‘A’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
ATTACHMENT ‘B’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
ATTACHMENT ‘C’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
BSR/ASHRAE Addendum f
to ANSI/ASHRAE Standard 15-2007
Public Review
Draft
_____________________________________
ASHRAE Standard
Proposed Addendum f to
Standard 15-2007, Safety
Standard for Refrigeration
Systems
First Second Public Review (October
March 20072008)
(Draft Shows Proposed Changes to
Current Standard)
This draft has been recommended for public review by
the responsible project committee. To submit a
comment on this proposed addendum, use the comment
form and instructions provided with this draft. The draft
is subject to modification until it is approved for
publication by the Board of Directors and ANSI. Until
this time, the current edition of the standard (as
modified by any published addenda on the ASHRAE web
site) remains in effect. The current edition of any
standard may be purchased from the ASHRAE
Bookstore @ http://www/ashrae.org or by calling 404636-8400 or 1-800-527-4723 (for orders in the U.S. or
Canada).
This standard is under continuous maintenance. To
propose a change to the current standard, use the
change submittal form available on the ASHRAE web
site @ http://www/ashrae.org.
The appearance of any technical data or editorial
material in this public review document does not
constitute endorsement, warranty, or guaranty by
ASHRAE of any product, service, process, procedure, or
design, and ASHRAE expressly disclaims such.
© August 13, 2007. This draft is covered under ASHRAE
copyright. Permission to reproduce or redistribute all or
any part of this document must be obtained from the
ASHRAE Manager of Standards, 1791 Tullie Circle, NE,
Atlanta, GA 30329. Phone: 404-636-8400, Ext. 1125. Fax:
404-321-5478. E-mail: [email protected].
AMERICAN SOCIETY OF HEATING, REFRIGERATING
AND AIR-CONDITIONING ENGINEERS, INC.
1791 Tullie Circle, NE Atlanta GA 30329-2305
BSR/ASHRAE Addendum f to ANSI/ASHRAE Standard 15-2007, Safety Standard for Refrigeration Systems
First Second Public Review Draft
(This foreword is not part of this standard. It is merely informative and does not contain
requirements necessary for conformance to the standard. It has not been processed according
to the ANSI requirements for a standard and may contain material that has not been subject to
public review or a consensus process. Unresolved objectors on informative material are not
offered the right to appeal at ASHRAE or ANSI.)
Foreword
There has been a trend toward increased use of cascade systems in refrigeration applications. Cascade systems
are being used in supermarkets, refrigerated warehouses, and industrial plants. Carbon dioxide (R744) is
frequently being used and considered for use in the low temperature side of cascade systems. Because of its
pressure-temperature relationship it would be cost prohibitive and unnecessary to meet all the design pressure
requirements of section 9.2 for refrigeration systems using R744, since the required standby pressures for R744
are much higher than those experienced during normal operation. For example, the design pressure required to
meet an 80ºF temperature (as would be required to meet the provisions of 9.2.1(a) for a lowside portion of a
system) would be 970 psia. The standby pressures for R744 are much higher than the traditional design
pressure of commercial and industrial refrigerating systems.
Allowing the use of R744 as a secondary coolant or refrigerant in certain situations, the proposed change permits
a design philosophy that would allow limited releases of R744 to the atmosphere during unusual events, such as
an extended power failure with coincident heat gains that cause system pressures to rise above component
design pressures. Refrigerant vented to atmosphere during a power failure is likely to be a “de minimus” quantity
compared to losses from other reasons such as normal leakage in even the best maintained commercial and
industrial systems.
Note: In this addendum, changes to the current standard are indicated in the text by underlining
(for additions) and strikethrough (for deletions) unless the instructions specifically mention
some other means of indicating the changes. Only these changes are open for review and
comment at this time. Additional material is provided for context only and is not open for
comment except as it relates to the proposed substantive changes.
Addendum f to 15-2007
[Modify Section 9.2.1 as shown below.]
9.2.1 Design pressures shall not be less than pressure arising under maximum operating, standby, or
shipping conditions. When selecting the design pressure, allowance shall be provided for setting pressurelimiting devices and pressure-relief devices to avoid nuisance shutdowns and loss of refrigerant. The ASME
Boiler and Pressure Vessel Code,5 Section VIII, Division I, Appendix M, contains information on the
appropriate allowances for design pressure.
Refrigerating equipment shall be designed for a vacuum of 29.0 in. Hg (3.12 kPa). Design pressure for lithium
bromide absorption systems shall not be less than 5 psig (34.7 kPa gage). Design pressure for mechanical
refrigeration systems shall not be less than 15 psig (103.4 kPa gage) and, except as noted in Sections 9.2.2,
9.2.3, 9.2.4, and 9.2.5, and 9.2.6 shall not be less than the saturation pressure (gage) corresponding to the
following temperatures:
a. Lowsides of all systems: 80°F (26.7°C).
b. Highsides of all water-cooled or evaporatively cooled systems: 30°F (16.7°C) higher than the summer 1%
wet-bulb for the location as applicable or 15°F (8.3°C) higher than the highest design leaving condensing
water temperature for which the equipment is designed or 104°F (40°C), whichever is greatest.
c. Highsides of all air-cooled systems: 30°F (16.7°C) higher than the highest summer 1% design dry-bulb for
BSR/ASHRAE Addendum f to ANSI/ASHRAE Standard 15-2007, Safety Standard for Refrigeration Systems
First Second Public Review Draft
the location but not lower than 122°F (50°C).
[Add a new section, Section 9.2.6, after Section 9.2.5.]
9.2.6 When a refrigerating system utilizes carbon dioxide (R744) as a refrigerant in a cascade refrigerating
system or as a heat transfer fluid, the system design pressure of the R744-containing components shall be
not less than the higher of the following two pressures: 500 psig or a at least pressure 250% higher than the
saturation pressure corresponding to the at its warmest location in the circuit the circuit under maximum
operating conditions where liquid and vapor may be present. In a cascade refrigerating system, the design
pressure of the R744-containing components in each circuit shall be at least 20% higher than the maximum
direct pressure developed a pressure-imposing element or that corresponding to the saturation pressure at
the warmest location under maximum operating conditions where liquid-vapor refrigerant may be present..
2
ATTACHMENT ‘D’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
ATTACHMENT ‘E’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
Current ASHRAE Standard 15-2007 wording:
9.4.3
A pressure-relief device to relieve hydrostatic pressure to another part of the
system shall be used on the portion of liquid-containing parts of the system that is
capable of being isolated from the system during operation or service and that will
be subjected to overpressure from hydrostatic expansion of the contained liquid
due to temperature rise.
Wording to replace the existing 9.4.3 that went out for public review:
Consideration must be given to hydrostatic expansion due to temperature rise of
liquid refrigerant trapped in or between closed valves. A hydrostatic relief device
or other means shall be provided to prevent over-pressurization. Relief into a
lower pressure portion of the system is allowed
Proposed new wording (1/15/08)
Definitions:
administrative control: the use of human action aimed at achieving a safe level of
performance from a system or subsystem
engineering control: the use of sensors, actuators, and other equipment to achieve a safe
level of performance from a system or subsystem without the aid of human interaction
9.4.3
Hydrostatic expansion. Consideration shall be given to pressure rise resulting
from hydrostatic expansion due to temperature rise of liquid refrigerant trapped in
or between closed valves.
9.4.3.1 If trapping of liquid with subsequent hydrostatic expansion can occur during
operation, standby, shipping, or power failure, engineering control(s) shall be
used that are capable of preventing the pressure from exceeding the design
pressure. Acceptable engineering controls include, but are not limited to:
a) pressure-relief device to relieve hydrostatic pressure to another part of
the system
b)reseating pressure-relief valve to relieve the hydrostatic pressure to an
outdoor location meeting the requirements of 9.7.8.
9.4.3.2 If trapping of liquid with subsequent hydrostatic expansion can occur only during
maintenance, either engineering or administrative controls shall be used to relieve
prevent the hydrostatic over-pressure.
AMERICAN SOCIETY OF HEATING, REFRIGERATING AND
AIR-CONDITIONING ENGINEERS, INC.
FORM FOR RESPONSE TO CHANGE PROPOSAL
DATE ___January 28, 2007______
SSPC NO. : _15________
PROPOSAL NUMBER(S): ___15-06-12-0001-001_________________________
RESPONDER'S NAME:
__Douglas T. Reindl__________________________________________________
ADDRESS:
__432 North Lake St_________________________________________________
__Madison, WI 53706 USA__________________________________________
___________________________________________________________________
TELEPHONE:
_(608) 262-6381___________
FAX: __(608) 262-6209____________________
Proposed change accepted for public review without modification
Project Committee Action:
Proposed change accepted for public review with modification (See below)
X
Proposed change accepted for further study (See below)
Proposed changed rejected (See below)
CM Proposal:
The following changes are proposed:
Insert the following between 9.7.8 and 9.7.8.1:
Exemption: Pressure relief devices and fusible plugs may discharge at a location below the 15 ft height specified above
provided that all the following conditions are true and the other requirements of 9.7.8 are met:
•
•
•
The refrigerant is classified in Group A1 in Table 1.
The system location meets the criteria for “Industrial Occupancy” or “Commercial Occupancy” where the relief discharge is located at least 20
ft from the nearest pedestrian walkway and is within an access controlled area (e.g. fenced area, on a roof, etc.)
The system is located outdoors and that the formation of an oxygen deficient atmosphere is not credible.
The author of the proposed change notes a competing concern with metal fatigue on the relief vent line as a result of equipment vibration and cantilevered
loads due to the weight of the vent tail pipe (particularly for piping larger than 1 inch and with screwed connections). Furthermore, the author expressed
concerns over the possibility of rainwater and condensation infiltrating the vent piping and potentially corroding relief valve springs. In summary, the
proposed change is intended to preserve safety and enhance mechanical integrity.
Revised: 7.5.2006
Project Committee Response:
A subcommittee has been formed to study this further and, potentially, develop
alternative provisions to accommodate these situations.
cc: Manager of Standards, ASHRAE, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305
Revised: 7.5.2006
ATTACHMENT ‘F’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
ATTACHMENT ‘G’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
Relief Valve Dispersion
Modeling Using PHAST
Martin L. Timm, P.E.
Praxair Inc.
716-879-7376
For SSPC 15 New York Meeting
For Committee Use Only;
Not For Distribution
General Comments

PHAST 6.53 is commercial dispersion
software used in various industries including
petrochemical, utility, offshore
Results shown here are preliminary; needs
more study
A “great” fit between predictions and field
measurements is 2:1; tool is sophisticated;
but results still somewhat qualitative
Cases Originally Considered
Range of Parameters, Cont.

Weathers:

Three weathers were used:
D5: (Unstable)
5 meter/second wind velocity, D stability, urban
surface type
F1.5: (Stable)
1.5 meter/second wind velocity, F stability,
rural surface type
G1: (Very Stable, Fog-like)
1.0 meter/second wind velocity, G stability,
rural surface type
NOTE: PHAST uses “Power Law” by
default for Wind Speed; Speed Lower Near
Ground!
Plume Behaviour

Heavier-than-air plume may slump to
ground if velocity and orientation do not
mix in enough air to make it neutral
density
Discharge at lower elevation means
lower wind velocity, less mixing
Pointing discharge towards ground
increases tendency to slump
R-22 Discharge Down at 15
feet, 60 lb/min
R-22 Discharge Down at 5
feet, 60 lb/min
R-22 Discharging Down, 60
lb/min, F1.5 Weather
Note varying velocity has an affect, but not dramatic
R-22 Discharging Down, 60
lb/min, F1.5 Weather
R-22 Discharging Down, 60
lb/min, F1.5 Weather
R-22:
Concentr. Vs.
Weather
Down
at 15 ft,
30 ft/sec
R-22:
Concentr. Vs.
Weather
Down
at 5 ft,
30 ft/sec
What about discharging
refrigerant up rather than
down?
R-22 Discharge Up at 5 feet,
60 lb/min
R-22 Discharged Up at 30
feet/second, RCL, G1
R-22:
Concentr. Vs.
Weather
Up
at 5 ft,
30 ft/sec
Conclusions From R-22
Modeling

Discharging DOWN near ground appears
viable; refrigerant unlikely to rise into
breathing zone while still highly concentrated
Discharging UP at 5 ft. elevation, and with
>30 feet/second velocity provides dilution
with little risk of “slumping” back to ground

Immediate mixing and dilution
Avoids accumulation in low spots, along walls, etc.

Possible issue with water/snow entering pipe

Ammonia:

For warm gas (95F) discharge in stable
air, gas rises after discharge whether
pointed up or down
Downwind distance much greater at
RCL due to much lower value of RCL
Ammonia Discharging Down,
60 lb/min at 15 or 5 feet
Some results better, some worse, at 5 feet discharge
Ammonia Discharge at 15
feet; Up vs. Down
Ammonia Discharge at 15
feet; Up vs. Down: Closeup
Conclusions From Ammonia
Modeling

Need to do more evaluation of
modeling to understand concentration
gradients
Up discharge appears better than down
discharge
Questions for Committee

What is acceptable exposure criteria?

Use RCL? Fraction of RCL?

Use F1.5 or G1 weather for “worst-case”
weather? (F1.5 is used by EPA for PSM/RMP)

Willing to consider upward discharge with a
minimum velocity?

Need to look at cold refrigerant discharge?

What about refrigerants with density close to
that of air???
Appendix
Range of Parameters, Cont.

Conc. Of Interest

1000 ppm for R-22
25 ppm for ammonia
Averaging Time:

User averaging time set to 18.75 seconds.
This is shorter than typical toxic averaging time of
600 seconds.
Intent was to capture peak concentrations, even if
they existed only for relatively short durations.
18.75 seconds was chosen since this is the default
PHAST averaging time for “short-duration”
flammability and explosion calculations.
R-22 Discharge Down at 1
feet, 60 lb/min
ATTACHMENT ‘H’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
ASHRAE Std. 15-2004
CM-15-05-12-0004/001 (K. McClure)
Re: 8.11.5 Proposed change REFRIGERANT VAPOR REMOVAL
When the exhaust is used to remove refrigerant vapors, the suction opening of the
exhaust fan ductwork to shall be no less than 24” from the floor or the lowest part of the
Room where refrigerant gas is likely to accumulate. All refrigerants except ammonia
Are heavier than air.
Comments
•Grammar is incorrect. Clarification is needed from the submitter. It is believed that what
was intended was to require suction opening to be no more than 24” from the floor.
•Regarding ammonia - There are other refrigerants that are lighter than air.
•Standard 15-2004 does not specify a height limit or provide for a specific location for
exhaust air duct inlet openings.
•Standard 15 requires that the inlet and outlet exhaust locations do not lead to
recirculation.
•The User’s Manual provides guidance by indicating that such duct inlets should be located
in the breathing space (a height of 5’ or less).
•The User’s Manual suggests that the inlet and outlet exhaust locations should set up
an effective sweeping action that does not leave any dead zones.
Recommendation
Incorporate the User’s Manual points above, incorporate a phrase indicating that inlet and outlet duct
location should take into account the density of the refrigerant relative to air [akin to 8.11.5 (d)].
• 8.11.5 (d) Location of the gravity ventilation openings shall be based on the relative density of the
refrigerant to air.
Recommended changes – 8.11.5 Placement after (b)
When the exhaust is used to remove refrigerant vapors, location of the ventilation openings
shall take into account the density of the refrigerant relative to air. The suction opening of
the exhaust fan ductwork shall be located as follows:
i) Suction exhaust openings for heavier-than-air refrigerants shall be located in the lower
portion of the breathing space not greater than 36 inches from the floor. Additional exhaust
opening(s) shall be located to exhaust pump pits or other low points in the machinery room where
applicable.
ii) Suction exhaust openings for lighter-than-air refrigerants shall be taken from the ceiling or wall
locations not lower than the highest 15% of the room’s volume.
•Regular ceiling offsets of 0.3% relative to the room volume that have a depth/width (where
width is the minimum horizontal dimension) ratio of 5 or greater shall be subject to (ii).
•Design of exhaust for machinery rooms with irregular ceiling profiles shall be via approved
engineering analysis.
•Note: Suction opening and return air opening locations should set up a sweeping action across the
room; for example, by locating openings on opposite sides of the room or in diagonally opposite
corners.
(Re-number clauses/sub-clauses.)
ATTACHMENT ‘I’
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ATTACHMENT ‘J’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
ATTACHMENT ‘K’
These Minutes were approved by vote of this Committee and are the official, approved record of the proceedings.
SSPC 15 Review of
2007 / 2008
Proposed Changes To The
International Mechanical Code
ASHRAE Winter Meeting
January 20, 2008
Code Change Proposal Review Task
• Review each relevant code change proposal
– code proposals can be found here:
http://www.iccsafe.org/cs/codes/2007-08cycle/ProposedChanges/index.html
• Make a recommendation on whether SSPC 15 wants
ASHRAE staff to speak in favor of a proposal, against a
proposal, or remain neutral.
– Each subcommittee would need to bring a recommendation to
the full committee on positions where SSPC 15 is in favor or
against a proposal.
Recommendation Options
•
Select from the following options:
– Strongly agree
• The Committee would like ASHRAE staff to speak in favor of this proposal during the
code hearings in September.
– Agree
• The Committee is in favor of this proposal, but we will leave it up to staff whether they
speak in favor of this proposal during the code hearings in September. **
– Neutral
• ASHRAE will not take a position. If you are neutral on a proposal, you do not need to
formally vote the position.
– Disagree
• The Committee disagrees with this proposal, but we will leave it up to staff whether they
speak against this proposal during the code hearings in September. **
– Strongly disagree
• The Committee would like ASHRAE staff to speak against this proposal during the code
hearings in February.
** Some of the reasons for not speaking at the hearing include:
(1) many other people are speaking and it is clear that ASHRAE would be just
another unnecessary "me too"
(2) speaking too many times dilutes the impact of what ASHRAE has to say
Recommendations
• For strongly agree, agree, disagree, or strongly disagree,
please prepare a few paragraphs to clarify your reasons
so that ASHRAE staff have adequate background
information. Please provide technical justification if
available. Your clarification and justification will help
ASHRAE make reasonable testimony and aid them in
any compromises that are proposed.
IMC Code Change Proposals
•
•
•
•
•
•
•
•
M24 – ventilation rates
M90 – pressure vessel code
M91 – tamper-proof service ports to prevent ‘huffing’
M92 – tamper-proof service ports to prevent ‘huffing’
M95 – machinery room requirements
M96 – refrigerant discharge
M97 – remote controls
M98 – refrigerant piping requirements
continued
continued
SSPC 15 Recommendations
•
•
•
•
•
•
•
•
M24 –
M90 –
M91 –
M92 –
M95 –
M96 –
M97 –
M98 –