Pumped Up
•
Unmatched Quality•
Superior Reliability•
Global Sales and Support•
Stock and Custom Orders Whether you’re an OEM pump manufacturer, a pumpassembler or a maintenance and repair professional, there’s a Baldor•Reliance® motor designed and manufactured for your specific motor-driven pump system application.
With Baldor•Reliance low and medium voltage horsepower ratings to 15,000 in single or three phase designs including explosion-proof, close-coupled, vertical P-base, submersible and immersible, no other motor manufacturer offers more choices, quality or pumped up reliability than Baldor.
baldor.com 479-646-4711
©2015 Baldor Electric Company
“The fi nancial world never stops, so having a dependable power source for our data center is critical. Our system was built to be redundant so we can perform maintenance without interrupting power. Effective and effi cient, our Cat® C32 diesel generator sets give us 2 MW of power that seamlessly step in. We’ve had outages that didn’t slow us down for a second and went largely unnoticed. Backed by Cat power, we’ve designed and built one of the most effi cient data centers in North America.”
© 2015 Caterpillar. All Rights Reserved. CAT, CATERPILLAR, BUILT FOR IT, their respective logos, “Caterpillar Yellow,” the “Power Edge” trade dress, as well as corporate and product identity used herein, are trademarks of Caterpillar and may not be used without permission.
DIESEL
|
GAS|
POWER PLANTS|
RENT ALLearn more at www.cat.com/globalrelay
100 PERCENT UPTIME. 365 DAYS A YEAR.
I’M DUFF REID. I RUN CAT
®DIESEL GENERATOR SETS.
CONSULTING-SPECIFYING ENGINEER (ISSN 0892-5046, Vol. 52, No. 2, GST #123397457) is published 11x per year, monthly except in February, by CFE Media, LLC, 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Jim Langhenry, Group Publisher /Co-Founder; Steve Rourke CEO/COO/Co-Founder. SPECIFYING ENGINEER copyright 2015 by CFE Media, LLC. All rights reserved.
CONSULTING-SPECIFYING ENGINEER is a registered trademark of CFE Media, LLC used under license. Periodicals postage paid at Oak Brook, IL 60523 and additional mailing offi ces. Circulation records are maintained at CFE Media, LLC, 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. E-mail: [email protected]. Postmaster: send address changes to CONSULTING-SPECIFYING ENGINEER, 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Publications Mail Agreement No. 40685520. Return undeliverable Canadian addresses to: 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Email: customerservice@ cfemedia.com. Rates for nonqualifi ed subscriptions, including all issues: USA, $150/yr; Canada/Mexico, $180/yr (includes 7% GST, GST#123397457); International air delivery $325/yr. Except for special issues where price
changes are indicated, single copies are available for $30.00 US and $35.00 foreign. Please address all subscription mail to CONSULTING-SPECIFYING ENGINEER, 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Printed in the USA. CFE Media, LLC does not assume and hereby disclaims any liability to any person for any loss or damage caused by errors or omissions in the material contained herein, regardless of whether such errors result from negligence, accident or any other cause whatsoever.
DEPARTMENTS
07 | Viewpoint
Work smarter, not harder
09 | Research
Seven key findings for the fire and life safety industry
11 | Career Smart Is an international assigment right for you?
12 | MEP Roundtable Learning objective: Designing K-12 schools
COVER STORY
26
|
Integration: BIM design
Building information modeling (BIM) is used frequently when working across multiple disciplines, including mechanical, electrical, plumbing, and fire protection engi-neering, and also with other stakeholders such as archi-tects and contractors.
ED PAUL
19 | Codes & Standards Piping arrangements for fire pumps
25 | Digital Edition Exclusives
Using IPD and Lean in building design
LCCA for HVAC systems
47 | Advertiser Index
48 | Future of Engineering
Key political trends in green building
FEATURES
32
|
Energy performance in
mission critical facilities
Mission critical facilities, such as data centers, are judged carefully on their energy use. Engineers should focus on the codes and standards that dictate energy performance and how building energy performance can be enhanced.
BILL KOSIK, PE, CEM, BEMP, LEED AP BD+C
40
|
Selecting fire pumps
The key for fire protection engineers is to understand the requirements of both NFPA 20 and NFPA 70 to properly choose and configure a fire pump so that the fire protec-tion systems can serve their intended use.
ALLYN J. VAUGHN, PE, FSFPE, and RICK REYBURN, PE
3
www.csemag.com Consulting-Specifying Engineer • MARCH 2015
MARCH 2015
ON THE COVER: This overall view of a building shows a single mechanical, electrical, plumbing, and fire protection (MEP/ FP) design model representing accurate location and overall dimensions of equipment and systems. This image is rendered from a single Revit model containing all MEP/FP disciplines. Courtesy: Arup
AUTOMATION & CONTROLS COMMUNICATIONS ELECTRICAL
FIRE, SECURITY & LIFE SAFETY
HVAC LIGHTING PLUMBING
ENGINEERING DISCIPLINES
Use the icons to identify topics of interest.Upcoming webcasts
Register for upcoming webcasts and earn American Institute of Architects accredited learning units (LU). Can’t watch
it live? Watch it on-demand at www.csemag.com/webcast.
March 19: Critical Power: Standby power for mission critical facilities
4 Consulting-Specifying Engineer • MARCH 2015 www.csemag.com
online now
cse
mag.
com
Is your firm an
MEP Giant?
The 2015 MEP Giants program lists the top 100 mechanical, electrical, plumbing (MEP),
and fire protection engineering firms in the United States. The in-depth analysis of these firms appears in the August issue and reveals what’s going on in the industry and how it has changed over the past few years. Special emphasis is placed on com-missioning firms in a separate report each October.
Your completed submission is due April 3, 2015. Please note that only one person may complete this form on behalf of your company. You can learn more about the program at: www.csemag.com/giants.
When engineering systems in K-12 schools,
what is the most difficult issue you face?
Read the Q&A about K-12 schools on page 12. To view more poll results, visit www.csemag.com/poll/cse. *New information gathered in 2015.
Codes and standards
Fire and life safety Automation and controls Energy efficiency, sustainability HVAC *Lighting and lighting controls Electrical and power
37% 17% 14% 20% 12% 4% 19% 17% 10% 17% 8% 17% 8% 2014 2015
Top articles of the week
Each week, Consulting-Specifying Engineer highlights the top articles from the previous week based on the feedback from the website viewers. To see past articles from each week, search “Top 5 Consulting-Specifying Engineer articles.”
2015
2015
Web exclusives
Visit www.csemag.com/archives for these Web exclusive articles:
NFPA 72 and 720 code changes Sustainable alternative refrigerant
products to be released this year Hankins & Anderson (H&A) announces
Rob McAtee to be the new director of energy and sustainability services. 2015 NEBB Conference to focus on
HVAC, BAS issues and standards
Read this on
your tablet
The tablet and digital editions of this publica-tion are greatly enhanced and have unique content for digital subscribers. Update your subscription at: www.csemag.com/subscribe.
Pure Power:
Critical Power and
Energy Solutions
Pure Power has been enhanced to include additional information including topics like mission critical facilities, energy efficiency,
electri-cal and power systems, and much more. Read it at www.csemag.com/purepower. Consulting-Specifying Engineer is on Facebook, Google+, LinkedIn, Twitter, and SlideShare. Follow Consulting-Specifying Engineer, join the discus-sions, and receive news and advice from your peers.
Facebook: www.facebook.com/CSEmag Google+: http://google.com/+csemag LinkedIn: http://tinyurl.com/CSElinkedin Twitter: www.twitter.com/AmaraRozgus www.twitter.com/CSEmag SlideShare: www.slideshare.net/ConsultingSpecifyingEngineer Facebook: www.facebook.com/CSEmag LinkedIn: http://tinyurl.com/CSElinkedin Google+: http://google.com/+csemag Twitter: www.twitter.com/AmaraRozgus SlideShare:
James Puritch
Vice President, R&D Camosun & UVic Co-op Alumnus
Headquartered in Victoria, British Columbia, in a modern and environmentally constructed LEED Platinum-Certified facility, we design and develop internet-connected building controls for a wide range of green buildings, including schools, hospitals, universities, recreational and commercial facilities. To learn more about our solutions for sustainability, and opportunities in the green buildings industry, please visit our website or sign-up for a facility tour at:
www.reliablecontrols.com/corporate/facility/tour.php
Honoring Engineering Leadership
Submit your firm’s data to be considered for the
Consulting-Specifying Engineer 2015 MEP Giants program
and be among the top mechanical, electrical, plumbing
(MEP), and fire protection engineering firms in North America.
Your firm’s information will be included in the printed and
online MEP Giants poster, featured in the
Consulting-Specifying Engineer August 2015 issue.
The in-depth analysis of these firms appears in August
and reveals what’s going on in the industry, and reveals
engineering trends over the past few years. Special
emphasis will be placed on commissioning in a separate
report in October.
Nominations for the 2015 MEP Giants are now open!
Go to
www.csemag.com/giants
to download the official
2015 MEP Giants submission form.
NOMINATION
DEADLINE:
To participate in the
2015 MEP Giants,
submit your firm’s
information by
Friday, April 3, 2015.
PRESENTED BY:
Sponsored by:
1111 W. 22nd St. Suite 250, Oak Brook, IL 60523 630-571-4070 Fax 630-214-4504
1111 W. 22nd St. Suite 250, Oak Brook, IL 60523
Editor’s Viewpoint
Amara Rozgus,
Editor in Chief
7
www.csemag.com Consulting-Specifying Engineer • MARCH 2015
Work smarter, not harder
A
t a recent gathering, I wastalk-ing to a longtime high-voltage electrician. I knew that he’d been laid off for close to 2 years. But when I asked how work was going, his face lit up and he said he was busy. So busy, as a matter of fact, that he felt guilty for putting in overtime. He hadn’t seen overtime pay in some time, and was happy to say that he felt that the construction industry was on the mend.
In a different conversation with engineers based out of Houston, I heard similar sentiments. In one case, an electrical engineer was putting in 50 to 60 billable hours per week, and could work even more due to a heavy work-load. Projects were rolling in, and they needed to work more hours, hire addi-tional staff, and streamline their project review processes to keep up.
Finally, chatting with manufacturers at a conference earlier this year, I learned about several ways they’re enhancing products and systems to help engineers make faster calculations, learn new sys-tems more quickly, and specify familiar products without having to request detailed information because it’s already available at the touch of a button.
Within all levels of the architecture, engineering, and construction industry, the “work smarter, not harder” mantra keeps bubbling to the surface. This low rumble will likely become a dull roar in the near future as fast-growing industries, like hospitality,
manufac-turing, and health care, continue their upward climb.
To work smarter, engineers should take note of a few things:
Many manufacturers are now providing calculators, tools, and other specialized software to help engineers work through a proposal or specifica-tion more quickly. Ask your manufac-turer rep to explain them to you, and incorporate them into your proposals and workflow to save time on designs.
Keeping on top of industry trends is key to the business development process. Data may come from busi-ness-to-business references, research reports, or education sessions. Make sure someone on your team remains on the cutting edge to give your firm that extra leg-up within the marketplace.
Succession planning takes time but pays back when done correctly. Engi-neering firms approach this in different ways—some hire straight out of college and mold them to fit the firm’s needs, while others hire people with much-needed knowledge and abilities already in place. Both are good approaches, but without training and mentoring, neither will play out in the long term.
Think differently—and encourage your team to contribute ideas from out-side the engineering community. Some of the best ideas are “borrowed” from divergent industries—think TED talks, Google’s hiring practices, or about other nontraditional thought leaders.
CONTENT SPECIALISTS/EDITORIAL
AMARA ROZGUS, Editor in Chief/Content Manager
630-571-4070 x2211, [email protected]
AMANDA PELLICCIONE, Director of Research
630-571-4070 x2209, [email protected]
MICHAEL SMITH, Creative Director
630-779-8910, [email protected]
KEMMIE TURPIN, Digital Media and Circulation Coordinator
630-571-4070 x2223, [email protected]
EDITORIAL ADVISORY BOARD
ANIL AHUJA, PE, LEED AP, RCDD,
President, CCJM Engineers, Chicago
PETER ALSPACH, PE, LEED AP BD+C,
Associate Principal, Mechanical Engineer, Arup, Seattle
J. PATRICK BANSE, PE, LEED AP,
Senior Mechanical Engineer, Smith Seckman Reid Inc., Houston
JERRY BAUERS, PE,
National Program Executive,
Outcome Construction Services LLC, Kansas City, Mo.
MICHAEL CHOW, PE, LEED AP BD+C,
Principal, Metro CD Engineering LLC, Powell, Ohio
JASON GERKE, PE, LEED AP BD+C, CXA,
Mechanical Engineer, GRAEF, Milwaukee
JOSHUA D. GREENE, PE,
Vice President, RJA Group Inc., Chicago
RAYMOND GRILL, PE, FSFPE,
Principal, Arup, Washington, D.C.
DANNA JENSEN, PE, LEED AP BD+C,
Associate Principal, ccrd partners, Dallas
WILLIAM KOFFEL, PE, FSFPE,
President, Koffel Associates Inc., Columbia, Md.
WILLIAM KOSIK, PE, CEM, LEED AP BD+C, BEMP,
Principal Data Center Energy Technologist, HP Technology Services, Chicago
KENNETH KUTSMEDA, PE, LEED AP,
Engineering Design Principal, Jacobs Engineering Group, Philadelphia
KEITH LANE, PE, RCDD, LC, LEED AP,
President, Lane Coburn & Assocs., Seattle
JULIANNE LAUE, PE, LEED AP BD+C, BEMP,
Senior MEP Engineer, Center for Sustainable Energy, Mortenson Construction, Minneapolis
KENNETH L. LOVORN, PE,
President, Lovorn Engineering Assocs., Pittsburgh
DAVID LOWREY,
Chief Fire Marshal, Boulder (Colo.) Fire Rescue
MICHAEL MAR, PE, LEED AP,
Senior Associate, Environmental Systems Design Inc., Chicago
BRIAN MARTIN, PE,
Electrical Engineer, CH2M Hill, Portland, Ore.
DWAYNE G. MILLER, PE, RCDD, AEE CPQ,
Chief Executive Officer, JBA Consulting Engineers, Hong Kong
SYED PEERAN, PE, Ph.D.,
Senior Engineer, CDM Smith Inc., Cambridge, Mass.
BRIAN A. RENER, PE, LEED AP,
Associate, SmithGroupJJR, Chicago
RANDY SCHRECENGOST, PE, CEM,
Austin Operations Group Manager and Senior Mechanical Engineer, Stanley Consultants, Austin, Texas
GERALD VERSLUYS, PE, LEED AP,
Principal, Senior Electrical Engineer, TLC Engineering for Architecture, Jacksonville, Fla.
MIKE WALTERS, PE, LEED AP,
Check out Consulting-
Specifying Engineer’s
eNewsletters!
Providing helpful and
specific information
that’s directly applicable
to your career.
•
CSE Codes and Standards
•
Electrical Solutions
•
Fire and Life Safety
•
HVAC Solutions
•
NewsWatch:
Data Centers
Educational Facilities
Hospitals
Office Buildings
•
Product and Media Showcase
•
Pure Power
Sign up today! Go to
www.csemag.com/newsletters
e
Newsletters
9
www.csemag.com Consulting-Specifying Engineer • MARCH 2015
research
2015 FIRE AND LIFE SAFETY STUDY:
Seven key findings for the
fire and life safety industry
R
espondents to theConsulting-Specifying Engineer 2015 Fire
and Life Safety Study identified seven important high-level findings impacting the fire and life safety industry today:
1. Building structures: The top
building structures respondents specify, design, or make fire and life safety system product selections for are office buildings (68%), industrial/ manufacturing facilities/warehouses (60%), and government buildings/ military facilities (55%).
2. Systems specified: More than
70% of respondents specify or expect to specify detection products—includ-ing control systems, dampers, and fire, smoke, heat, and linear detectors.
3. Systems value: The average total
annual dollar amount of fire and life safety systems specified for new and existing systems is $1.9 million, a 12% decrease from 2014.
4. Challenges: When asked about
the challenges to fire and life safety
system design and specifications, 65% or more indicated subjective interpretation of regulations by code authorities, inadequate design budget, and the authority having jurisdiction (AHJ) or code enforcement not under-standing new systems as constant hurdles.
5. Disciplines: Local AHJs or fire
officials have the most input and impact on fire and life safety design, according to 65% of respondents, fol-lowed by owners (40%), architects (35%), and electrical engineers (35%).
6. Design factors: Product quality
(70%), service support (50%), and manufacturer’s reputation (45%) were identified as extremely important to respondents when selecting fire and life safety systems.
7. Experience: The average
engi-neer involved in fire and life safety systems has been in the industry for 21 years.
View additional findings at
www.csemag.com/2015FireLifeSafety.
www.csemag.com/research FOR MORE RESEARCH INFORMATION Electrical, power challenges
Inadequate
budget delivery speedProjectProject efficiencyEnergyEnergy Inadequate
82%
71%
58%
Source: Consulting-Specifying Engineer, CFE Media
Average total annual dollar amount of fire,
life safety systems
2013 +6.5% -12.1% 2014 2015 $2,031,383 $2,163,750 $1,902,625
>85%
of lightingengi-neers specify LEDs; T5s, T8s, or T12s (any size); and/or lighting controls. Source: Consulting-Specifying Engi-neer 2014 Lighting and Lighting Controls Study
9 out of 10
mechanical engineers rank product quality, product energy efficiency, manufacturer’s reputation, service support, and initial product cost as very important factors for selecting HVAC products. Source: Consulting-Specifying Engineer 2014 HVAC and Building Automation Systems Study.
50%
or more engineers frequently use prescriptive or open (proprietary) fire and life safety specifications issued by their firm. Source: Consulting-Specifying Engi-neer 2015 Fire and Life Safety StudyMore research
Quarterly, Consulting-Specifying Engineer surveys its audience on four topics: fire and life safety, elec-trical and power, lighting and light-ing controls, and HVAC and buildlight-ing automation systems. All of the reports are available online at www.csemag.com/research.
SCOUT Technology gives you 24-hour access to your compressed air system’s performance via a web-based dashboard. Analyze in-depth data wirelessly on your computer or mobile device.
PROVIDE REAL-TIME DATA AND CUSTOMIZED ALERTS
Together we can
ENGINEERING
YOUR
SUCCESS.
www.parker.com/Transair 480 830 7764
Transair
®
powered by
SCOUT
™
Technology
input #5 at www.csemag.com/information
In 2014, Consulting-Specifying Engineer surveyed its audience members responsible for decisions related to the design of HVAC and/or building automation systems (BAS) products and services within their firms.
According to the data in this report, half of HVAC and building automation products specified by engineering firms for new and existing buildings are valued at more than $1 million, compared to 59% in 2013 and 47% in 2012.
Download the new Consulting-Specifying Engineer 2014 HVAC and Building Automation Systems Research today!
www.csemag.com/2014HVACBAS
Improve your HVAC and BAS business with CSE Research
Turning research into insights to make better business decisions
and/or building automation systems (BAS) products and services
A
former colleague recently asked me for help in identifying all the things she needed to consider in deciding whether to accept an international proj-ect assignment. The position was a 2-year assignment in Paris that would be a nice step up in responsibility and pay. And as a mid-level team leader, this friend was hoping the assignment would advance her career path to a more senior level position upon her return. And well, it was Paris—she was definitely dazzled by the idea that weekends could be spent traveling and exposing her children to the European lifestyle.In the right circumstances, foreign assignments can turbocharge your career path. The professional challenges that come with prolonged project assignments, business development roles, or operations can put all your skills to the test and help you develop some new ones. Cultural differences, language barriers, limited local resources—especially in develop-ing countries—will force you to use both your technical as well as your softer skills. Success in these types of assignments can cast you in a different leadership light with your company’s senior management, espe-cially when you are able to demonstrate flexibility, adaptability, and the ability to lead an often diverse team to success—all skills needed for senior management posi-tions. And in your company or field, such an assignment may even be a prerequisite for a senior position.
But before you run out to get your passport renewed and start volunteering
for foreign assignments, consider the fol-lowing:
1.
Is the assignment in a country where you are comfortable working? Examine your personal and professional values and make sure the local business practices and culture align with them.2.
Where is your internal sponsor/ mentor, and who will keep you top-of-mind in the home office while on this assign-ment? You do not want to suffer from “out of sight, out of mind” while slaying drag-ons for your company in a foreign market.3.
What is the duration of the assign-ment, and what are your expectations upon completion? Make sure you and your employer are clearly in agreement on your specific career expectations when the assign-ment is complete. This is not just alignassign-ment on career advancement but also continued employment. I have seen multiple cases where a colleague returns from an overseas assignment to find there is not a position for him or her at home. This can especially be the case in heavy project-based environ-ments where there is not room for another billable individual on existing projects.4
.
Consider the impact on your family. Ask yourself if your family can survive and thrive in the assigned country. And don’t assume that because the assignment is in a cosmopolitan, westernized country that your family or spouse will do well. Thesimple act of going to a grocery store to find the makings for your favorite chili recipe or finding a family dentist can be a huge chal-lenge. Consider asking your employer to allow you to take your family to the country before the assignment starts to experience first-hand what life will be like. Don’t just limit your trip to house hunting and visiting your kids’ school options; spend time with other expatriate families to really under-stand what life is like there.
5.
Consider how your life will change with the international experience. Living and working abroad will change you, and are you OK with that? Everyone I know with international experience has returned to the U.S. with a different perspective that makes their views and decision-making multidimensional, myself included. But if you fear change or are uncomfortable with allowing a different professional and cultural experience to affect you, then an international assignment is probably not a wise choice.Jane Sidebottom is the owner of AMK LLC, a management and marketing con-sulting firm that provides market develop-ment and growth expertise to small- and medium-size firms. She has more than 20 years of management and leadership expe-rience in both consulting engineering and Fortune 100 organizations. Sidebottom is a graduate of the University of Maryland.
Is an international assignment
right for you?
Consider these 5 questions if you’d like to work abroad.
BY JANE SIDEBOTTOM
AMK LLC, Louisville, Ky.
11
www.csemag.com Consulting-Specifying Engineer • MARCH 2015
Career
Smart
Read the longer version of this online at: www.csemag.com/careersmart.
12 Consulting-Specifying Engineer • MARCH 2015 www.csemag.com
CSE: Please describe a recent K-12 school project you’ve worked on.
David Ellis: I was involved with the design of a complete renovation of a 330,000-sq-ft high school located in Washington, D.C. This project included a natatorium, performance auditorium, arts center, gymnasium, two kitchens, and academic classrooms, including labs. The high-performance conditioning and ventilation system for this school involved the matching of a hydronic variable refrigerant flow (VRF) system, using a ground coupled approach along with a dedicated outdoor air system (DOAS). Design was performed using a design assist contract, which included a great deal of cost control input from the contractor, as this allowed for an accelerated construction schedule while containing costs. As this was a renovation, BIM software proved valuable for coordination.
Nestor Ortiz: I am the lead project officer for the school construction authority (SCA) construction management for an expansion/ renovation of a public school in Queens, N.Y. We are adding 43,000 sq ft to an existing school. The new building will have four floors and a mechanical equipment room located on the roof. This expansion will be connected to the existing school at all three floor and cel-lar levels. The school will become Americans With Disabilities Act (ADA) compliant as well as provide two elevators, a gymatorium, a new kitchen/cafeteria, eight new classrooms, a music room, a library, a science resource room, and an art room. In case of emergency,
the school will be able to run on emergency backup due to its new generator located at the roof level.
John C. Palasz: I was the lead mechanical engineer for a boiler renovation project at Carl Schurz High School. A historic landmark on Chicago’s northwest side, Schurz is a 400,000-sq-ft building housing more than 2,500 stu-dents. The project included the replacement of the steam boilers with new 500-hp low-pressure steam boilers with the addition of steam-to-water heat exchangers, two 365-ton centrifugal chillers and cooling towers, as well as all pumps, feedwater, chemical treatment, and accessories to provide a dual-temperature water plant. In addition, the air-handling sys-tems were refurbished and retrofitted with new dual-temperature coils, fan motors, filters, and dampers. The project also included all associ-ated controls and a new building automation system (BAS).
CSE: How have the characteristics of K-12 school projects changed in recent years, and what should engineers expect to see in the near future?
Ortiz: There are several safety features that have been added to schools for security rea-sons, such as cameras throughout the school grounds and designated rescue rooms. Aside from security upgrades, the engineers can expect mechanical, electrical, plumbing (MEP), and fire protection systems that are more self-sufficient and efficient. They will make the school custodian’s life easier as the equipment
MEP
Roundtable
PARTICIPANTS
David Ellis, PE, CEM, LEED AP Senior Vice President
of Engineering
Allen & Shariff Engineering LLC Columbia, Md. Nestor Ortiz Senior Construction Engineer, Project Officer Parsons Brinckerhoff Long Island City, N.Y.
John C. Palasz, PE, HFDP Mechanical Engineer Primera Engineers Ltd. Chicago Nestor Ortiz John C. Palasz,
Learning objective:
Designing K-12 schools
In K-12 schools, technological advancements, code requirements,
and other demands placed on engineers are consistently increasing,
while limitations like budget restraints remain a challenge.
13
www.csemag.com Consulting-Specifying Engineer • MARCH 2015
will be able to communicate if there is an issue or service needed. The equipment will be able to run efficiently, in various modes, such as startup, occupied, unoc-cupied, and economizer mode.
Palasz: Similar to a number of other markets, K-12 school projects have start-ed to see more demanding design and construction schedules in recent years. Schools and districts are stretching their budgets in multiple directions to cover necessary building repairs, infrastructure upgrades to reduce energy costs, teacher salaries and pensions, utilities, and the desire for improved teaching technolo-gies such as smartboards and computers. As budgets stay the same or decrease and schedules decrease, these projects become a challenge. In the near future, engineers can expect to see an increase in the overall number of projects as aging buildings and rising energy costs drive the need for building control systems and high-efficiency design. The energy codes (International Energy Conservation Code and ASHRAE Standard 90.1) raise the bar for both renovation and new construc-tion projects, but this usually comes with a higher price tag. Furthermore, the long-term energy savings that are designed may not be realized. Commissioning the system after the initial setup as well as regularly scheduled user training can help to achieve or maintain the projected energy savings.
Ellis: Sustainability—in regard to energy—water, and acoustics have taken charge of the design approach. The U.S. Green Building Council’s LEED for Schools program has led to innovation in school design, where measures such as energy-efficient design, water conser-vation, and a focus on room acoustical performance has improved classroom effectiveness while improving the sus-tainability of the school project. As certi-fication programs ratchet up performance expectations, along with higher perfor-mance sustainability codes, expect the
drive to net zero to enter into the next generation of facilities that begin design within 5 to 10 years.
CSE: How does engineering sys-tems in K-12 schools differ from col-leges and universities?
Palasz: My experience is that college and university engineering systems are generally designed to encourage student enrollment. Expenses are seldom spared to ensure quiet and comfortable designs while systems are designed with a higher standard of quality. These systems can be designed to last 100 years or more. Additionally, classrooms are designed with more versatility to specifically allow for rapid furniture changes to allow for collaboration one day and independent work the next day. On the contrary, many K-12 projects are limited by bud-get, and improvements are made to bring the school up to par or code minimums. Budget constraints often limit the design approach, which results in equipment that is expected to last between 20 and 30 years.
Ellis: There are similarities, of course, but in general, along with the discrete
focus buildings, as opposed to the com-bined activities in schools, universities have the potential for campus-wide utili-ties and the hours of operation tend to be extended. In addition, university opera-tions staff typically have a higher level of training than the staff of K-12 schools.
CSE: Please explain some of the general differences between retrofit-ting an exisretrofit-ting school and working on a brand-new structure.
Ortiz: When working on retrofitting an existing school, some of the challenges entail upgrading current utility services (electrical system, water/sewer services, and/or gas service) or having to interface new with outdated equipment. Even with thorough surveying and planning, unfore-seen conditions inevitably occur when working in an existing building. When working with a brand-new structure, a critical factor will be complete coordina-tion of trades and compliance with all the latest codes and standards.
Ellis: Existing schools pose a challenge in adapting to existing structural and envelope constraints than that encoun-tered in new school approaches. Usually,
Figure 1: Primera Engineers was engaged to renovate the boiler at Chicago’s Carl Schurz High School, a historic landmark. The team replaced steam boilers with 500-hp, low-pressure steam boilers, added steam-to-water heat exchangers, two 365-ton centrifugal chillers, cooling towers, and other components. The project also included a new building automation system. Courtesy: Primera Engineers Ltd.
MEP
Roundtable
there is uncertainty in locating or identi-fying these existing constraints, and that leads to risk in containing construction costs. As such, renovation projects ben-efit from having a contractor involved early, providing demolition to reduce the uncertainty during design.
Palasz: Some of the general differenc-es between retrofitting an existing school and working on a brand-new structure are that retrofit projects often require more site survey work prior to construction and are likely occupied during construction. This introduces logistical challenges and requires additional design considerations. New structures allow for increased design flexibility in building shape and system type. That flexibility leads to an increased potential for energy savings from a tighter and more insulated envelope and/or a spacious mechanical room that allows for accessible, sustainable, and maintainable equipment that may be integrated directly
into the building type. Older structures seldom offer these opportunities.
CSE: Many schools require flex-ible space—building features that can be adapted to different uses as the school’s needs evolve. How do you take such requirements into consideration?
Palasz: By gathering as much infor-mation about the different uses and coor-dinating the ways that the space will be adapted, many system types may be elim-inated. If different space uses are few and known, then a system can be designed to have various modes to accommodate accordingly, such as a lab mode (using 100% exhaust), lecture mode, or disco mode. To be cost-effective when design-ing a flexible space, the design require-ments must be well-defined. One com-mon approach is to design added capacity
in the system to account for high occu-pancy, or additional computer equipment while incorporating the appropriate con-trols to reduce or shut off cooling, ventila-tion, or exhaust as needed. The controls help maintain energy efficiency, but over-sizing equipment to account for design flexibility may result in a high installa-tion cost.
Ortiz: My current project includes a gymatorium that is a combination of a gymnasium and auditorium. Aside from the two obvious functions, this space gives the school a location for kids to play on rainy days, a location the community could use for events, or a community ref-uge from natural disasters. The gymato-rium will have its own dedicated rooftop unit and emergency lighting that will be tied back to the school’s new emergency generator. The gymatorium will have chair storage and retractable basketball rims so the school can transition to dif-ferent sporting setups.
CSE: When designing integration monitoring and control systems, what factors do you consider?
Ortiz: Major components for design-ing integration monitordesign-ing systems and controls are efficiency and energy con-servation. For example, motion sensors are being used to shut off lights when there are no occupants in rooms, and mechanical equipment is designed using heat wheels to save energy and minimize heat loss.
Ellis: To the extent possible, opera-tional and maintenance complexity has to be reduced.
CSE: What are some common problems you encounter when work-ing on buildwork-ing automation sys-tems?
Ellis: Given the proprietary nature of most control manufacturers’ architectural approach, despite the drive toward open systems, defining architecture is still sub-ject to customization by each vendor.
ESL's TripleSwitch™ is designed to service critical operations facilities that have an automatic transfer switch and dedicated generator. The TripleSwitch uses three interlocked circuit breakers to isolate standby generator circuits during load bank testing. This unique design also provides a quick, safe method to connect to a portable generator for redundant backup portable generator for redundant backup
Make
Load Bank Testing
More
Convenient & Economical
800.922.4188 - 951.739.7020 - eslpwr.com - [email protected]
TripleSwitch™
3-Way Manual Transfer Switch 125A - 2000A up to 600VAC Type 3R Enclosure
UL/cUL 1008 Listed up to 800A
Watch Simplify Generator Load Bank Testing Video: eslpwr.com/TripleSwitchVideo
Easiest Way to Conduct Required Maintenance on Your Permanent Generator
SWITCHTM
17
www.csemag.com Consulting-Specifying Engineer • MARCH 2015
Ortiz: Some of the challenging prob-lems we have encountered with our expansion/renovation project are dealing with modifications of existing systems or integrating them with new ones. The older systems are sometimes obsolete and need to be integrated with the new system. To avoid further issues, the old system will be upgraded as well.
CSE: What codes, standards, or guidelines do you use as a guide as you work on these facilities?
Palasz: ASHRAE has great reference information available to engineers. Spe-cifically, for the work we do with Chicago Public Schools (CPS), the City of Chica-go code Chica-governs these projects. Likewise, CPS publishes an HVAC design guide and provides details, specifications, and invaluable input to optimize design main-tain consistency and reduce cost.
Ellis: In addition to current codes, each school district typically has its own design guidelines, and frequently LEED for Schools is employed.
Ortiz: The current school project complies with the 2008 New York City (NYC) building code, and some aspects of the 2014 codes. Many of the standards and guidelines are based on the needs of the school in coordination with the New York City Dept. of Education.
CSE: Which code/standard proves to be most challenging in such facilities?
Palasz: Meeting the prerequisites for LEED certification is typically the most challenging. Because projects are trend-ing toward tighter budgets and shorter design and construction schedules, the addition of a requirement to exceed the energy code while providing quiet ven-tilation presents a challenge.
Ellis: Given the typical approach of decoupling ventilation from condition-ing, acoustic performance is the biggest design challenge. New codes, especially the IECC and the International Green
Construction Code (IgCC), pose a docu-mentation problem that code officials want resolved by new documentation that increases production effort.
CSE: Energy efficiency and sustainability are often the No. 1 request from building owners during new building design. What is your experience in this area?
Palasz: My experience is that to achieve excellence in energy efficiency and sustainability, the designers need to work with building owners and approach it as a team effort. Prior to building occupancy, new buildings are being fine-tuned to balance system controls and flow rates to provide comfort with the designed operation. Adjusting systems often needs to occur for months and
requires adjusting for the heating season as well as the cooling season. I believe that striving for improved efficiency should be an ongoing effort that should not stop once the building is occupied. To do this, it is necessary to have ener-gy meters to establish a baseline and to track the system operation improve-ments or denigration from year to year. This information is also critical in deter-mining corrective actions for equipment replacement and/or operational adjust-ments to achieve cost savings.
Ellis: Energy performance and other sustainability practices have been involved in the majority of K-12 projects in the last few years, and going forward are to be a part of all projects based on the implementation of the new codes, in particular the IgCC.
CSE: What changes in fans, vari-able frequency drives, and other related equipment have you experi-enced?
Ellis: The biggest change in the design approach has been the introduction of de-coupling of ventilation from conditioning by the use of DOAS, and the application of VRF systems. DOAS allows for sub-stantial energy savings in the avoidance of conditioning unnecessary ventilation air, and VRF allows for low-energy transport of heat during periods of concurrent heat-ing and coolheat-ing. Of course, improvements in design and cost of variable frequency drives (VFDs) allows for more opportuni-ties for implementing the energy-saving advantages associated with variable flow, both air and water, and development of inexpensive pressure independent constant air regulators allows for the mixing of con-stant and variable flow ventilation on the same variable air volume (VAV) DOAS, which allows for ventilation savings with highly variable occupancy classrooms with fixed makeup spaces, such as labs.
Palasz: Over the past few years, I have experienced a change in the trend of using a roof-mounted return fan in an insulated housing (similar to a rooftop unit) to wrap-ping a mixed flow fan. This results in a lighter and more efficient design, which helps to decrease initial costs by reduc-ing the structural reinforcement require-ments. It also helps to improve the return on investment with a very efficient fan (up to 85% efficient). In regard to VFDs, they have become less expensive and more widely used to provide system flexibility and soft-start capability in addition to diag-nostic alarms.
“
Major components for designing integration monitoring systems and controls are effi-ciency and energy conservation. For example, motion sensors are being used to shut off lights when there are no occupants in rooms, and mechanical equip-ment is designed using heat wheels to save energy and mini-mize heat loss.”
—Nestor Ortiz
Read the longer version of this online at: www.csemag.com/archives.
Learn about the latest engineering trends
and technologies while earning CEU credits.
Check out some of our webcasts on topics like
•
HVAC: Alternative heating/cooling systems
•
Critical Power: Standby power for mission
critical facilities
•
Critical Power: Data center electrical efficiency
•
Energy efficiency: Variable frequency drives
(VFDs), variable speed drives (VSDs), and
motors
•
Lighting: LED codes and standards
•
Fire/life safety: Detection and notification
systems
•
Critical Power: Coordination, selective
coordination
•
Integration: Specifying building automation
systems (BAS) using ASHRAE Guideline
13-2014
•
Critical Power: Circuit protection
19
www.csemag.com Consulting-Specifying Engineer • MARCH 2015
E
ffective fire pump installations require fire protection engineers to consider numerous components, and correctly apply a range of design and installation standards. In addition to addressing the more obvious components that comprise a fire pump installation—such as the fire pump, driver, controller, and pump room— careful attention also needs to be given to the piping leading to, from, and around the pump and the equipment associated with that piping.While NFPA 20: Standard for the Installation of Stationary Pumps for Fire Protection serves as the principal standard addressing the sizing and installation of the associated piping, the next edi-tion being the 2016, other codes and standards such as NFPA 13, NFPA 14, NFPA 22, NFPA 24, NFPA 25, and NFPA 291, as well as the applicable building and fire codes, also need to be reviewed and correctly applied depending on the type of fire protection systems served by the fire pump.
Suction piping
The piping connecting the water supply to the fire pump is referred to as suction piping. It com-prises all piping, valves, and fittings that feed water to the pump’s suction flange. The selection and installation of such suction pipe material is addressed by NFPA 24, which specifies the use of certain types of iron, steel, concrete, plastic, and copper. In addition, NFPA 24 addresses how the pipe and fittings are to be joined together, depth of cover if the pipe is buried, protection of the pipe from freezing and other damaging events, joint restraint, and acceptance testing including flushing and hydrostatic tests.
NFPA 20 addresses the arrangement of the suction pipe and associated devices. Generally,
the suction pipe and associated devices need to be arranged in such a manner so as to mini-mize the likelihood of turbulent and imbalanced water flow entering the pump. Such conditions decrease overall pump performance, can result in a sudden system failure and can cause premature wear of system components.
The size of the suction pipe is influenced mostly by the fire protection system’s hydraulic demand as determined in accordance with the appropriate system installation standards, such as NFPA 13 or NFPA 14, and the size of the fire pump selected. NFPA 24 provides guidance on suction pipe sizes and generally states that for any system, the pipe should be at least 6 in. in nominal diameter. Smaller pipe sizes are permit-ted provided hydraulic calculations verify that the pipe can supply the necessary system demand at the corresponding required pressure.
NFPA 22 provides specific guidance with regard to suction piping connecting a water tank with the fire pump. For instance, if the suction tank exceeds 100,000 gal, the size of the suction pipe must be at least 10 in. in diameter (nominal dimensions). The smaller the pipe, the faster the water flow, and therefore more turbulent flow will occur. Increasing the pipe size lowers the flow velocity and reduces the occurrence of turbulence.
NFPA 20 includes more specific provi-sions about suction pipe where fire pumps are installed, and specifies certain pipe sizes. The philosophy is that suction pipe be sized so that when the pump is operating at its maximum flow rate, which is 150% of its rated capacity or the maximum flow available from the water supply, the gauge pressure at the pump suction flange
BY MILOSH PUCHOVSKY, PE, FSFPE, Worcester Polytechnic Institute, Worcester, Mass.
NFPA 20
addresses the
arrangement
of the suction
pipe and
associated
devices.
Codes
&
Standards
Piping arrangements
for fire pumps
NFPA 20 provides fire protection engineers with guidance on
design and installation of fire pumps and related components.
Codes
&
Standards
20 Consulting-Specifying Engineer • MARCH 2015 www.csemag.com
does not drop below -3 psi (-0.2 bar). Furthermore, the suction pipe is to be sized such that with the pump operating at 150% of its rated capacity, also referred to as pump’s overload point, the velocity in that portion of the suction pipe located within 10 pipe diameters upstream of the pump suction flange does not exceed 15 ft/sec (4.57 m/sec). Pipe flows in excess of this velocity are more prone to turbu-lence. Where the suction pipe differs in size from the pump suction flange, reduc-ers or increasreduc-ers are permitted to be used but must be of the eccentric tapered type and installed in such a way so
as to avoid air pockets. In addition to specifying suction pipe sizes based on the rated capacity of the fire pump, NFPA 20 also addresses other system attachments that could cause turbulent or imbalanced flow into the fire pump. Where backflow preventers or check valves are being considered, they are to be located a mini-mum of 10 pipe diameters from
the pump suction flange. If the backflow device incorporates butterfly valves, the device is to be installed at least 50-ft from the pump’s suction flange. In fact, the 50-ft criterion applies to any valve, other than an outside screw and yoke gate valve, installed in the suction pipe.
Elbows and tees in the suction pipe also warrant special consideration. Such devices are to be located and positioned with respect to the orientation of their centerline plane. Where the centerline plane is parallel to a horizontal split-case fire pump shaft, the elbow or tee needs to be located a distance at least 10 pipe diameters from the suction flange of the fire pump. If the centerline plane is per-pendicular to the horizontal split-case pump shaft, no limitations are placed on the location of the elbow or tee.
It is important to recognize that NFPA 20 only addresses the size of the suction pipe within 10 pipe diameters of the pump suction flange, while NFPA 22 addresses the size of the pipe connected to the tank. The provisions of NFPA 24 would apply
where the requirements of NFPA 20 and NFPA 22 do not take precedence.
Discharge piping
NFPA 20 defines discharge pipe and equipment as the pipe, valves, and fit-tings that extend from the pump discharge flange to the system side of the discharge control valve. Practically, any pipe, valve or fitting downstream of the fire pump’s discharge control valve is no longer con-sidered to be part of the discharge piping. Such pipe, valves, and fittings are con-sidered part of the supply piping for the
fire protection system being served by the fire pump. In the case of a sprinkler sys-tem riser, the requirements of NFPA 13 would apply from the point of the pump discharge control valve.
NFPA 20 addresses the size of the dis-charge pipe and associated fittings, and requires all of the aboveground discharge piping to be composed of steel. In certain cases the discharge pipe is permitted to be smaller in diameter than the suction pipe because the water flow velocity is not of the same concern on the discharge side of the pump. The size of the discharge pipe has an effect on friction loss, but that effect can be accounted for though hydraulic analysis. As with suction pipe sizes, NFPA 20 specifies minimum dis-charge pipe diameters based on the capac-ity rating of the fire pump.
A control valve is to be installed on the discharge piping so that the pump can be isolated for service and repairs. Additional valves are discouraged to minimize the possibility that a valve will be inadver-tently shut and not reopened—an
ever-present concern with water-based fire protection systems. The control valve is permitted to be any type of valve listed for fire protection service, including a but-terfly valve, because turbulence is not as critical on the discharge side of the pump. A check valve is also to be installed on the discharge piping, between the fire pump and the discharge control valve. The discharge check valve traps the high-er pressure in the fire protection system after the fire pump operation stops. The check valve also prevents other sources of water flow into the system, such as through a fire department con-nection, from flowing back into the fire pump.
NFPA 20 requires that the pressure rating of the dis-charge components, includ-ing all pipinclud-ing, fittinclud-ings, and valves, be adequate for the maximum total discharge pressure with the pump oper-ating at churn conditions at the pump’s rated speed.
Pump bypass piping
A bypass is an arrangement of piping around the fire pump that can be used to supply water to the fire protection system should the pump fail or be taken out of service. Such bypass piping is to be sized as required for the discharge pipe.
Bypass piping is required where the water supply is considered to be of “mate-rial value” to the fire protection system without the use of the fire pump. While this is a rather subjective requirement, bypass lines are usually required where the water supply is provided by a pressur-ized fire service main such as municipal waterworks or private fire service main. Where the water supply for the building is from a private stand-alone fixed sup-ply such as the suction tank, a minimum pressure due to the elevation head of the stored water in the tank is available but is not usually considered to be of material value. However, this should be verified through hydraulic analysis, and needs to be confirmed with the respective authori-ties having jurisdiction.
The size of the discharge pipe has an
effect on friction loss, but that effect
can be accounted for though hydraulic
analysis. As with suction pipe sizes,
NFPA 20 specifies minimum discharge
pipe diameters based on the capacity
rating of the fire pump.
21
www.csemag.com Consulting-Specifying Engineer • MARCH 2015
A check valve needs to be installed in the bypass piping so that the flow from the pump discharge cannot recirculate back to the pump suction. Additionally, control valves need to be installed on either side of the check valve so that the check valve can be isolated for maintenance.
Pressure maintenance pump
A fire pump should operate only dur-ing fire conditions or when it is bedur-ing tested. A fire pump should not be used to maintain system pressures under non-fire conditions. The activation of a non-fire pump provides an alarm signal as it indi-cates the operation of the fire protection system, and such fire pump activation under nonfire conditions would serve as a false alarm. Pressure maintenance pumps, also referred to as ”jockey” pumps, are used to maintain pressures within the fire protection system under nonfire conditions.
Many water-filled fire protection sys-tems are designed so that they are pres-surized upon their installation. A system check valve serves to maintain system pressures. During a fire event, the acti-vation of a sprinkler or the opening of a standpipe valve will cause a drop in system pressure, which will be sensed by the pressure switch in a fire pump controller. In turn, this will initiate acti-vation of the fire pump.
Minor pressure losses can also occur downstream of the fire pump check valve under nonfire conditions. Pressure losses can occur due to water seepage across check valves or leaky fittings, or chang-es in system temperature. With regard to temperature, air pockets are usually trapped in the system piping. Ambient temperature changes in proximity of the fire protection system piping will cause the air pockets to fluctuate in size, thus varying the relative pressure in the sys-tem piping. A large decrease in ambient temperature in the warehouse, such as might occur in an unconditioned space over a 24-hour period, can cause a nota-ble pressure drop, which could be sensed by the fire pump pressure switch.
Jockey pumps mitigate false alarms by compensating for small pressure fluctuations in system piping and return the system to its normal static pressure range under nonfire conditions. As with a fire pump, the jockey pump instal-lation will include a controller with a pressure switch. The jockey pump pres-sure switch is normally set at a higher pressure so that the jockey pump starts before the fire pump. Note that each controller, the one for the jockey pump and the one for the fire pump, must have its own independent pressure sens-ing line that connects the fire protec-tion system with the pressure switches in each controller.
Jockey pumps are high-pressure, low-flow pumps that typically cannot sustain system pressures after the activation of a single sprinkler. When a sprinkler oper-ates or a standpipe outlet is opened, the jockey pump operates but cannot main-tain adequate system pressure due to the relative high volume of water flow from an operating sprinkler or opened outlet as compared to that of a leaky fitting. The pressure within the system continues to fall until the fire pump starts and produc-es the required flow and prproduc-essure for the operating system.
Jockey pumps are not required as part of fire pump installation. However some means of maintaining system pressure under non-fire conditions without relying upon the fire pump as a pressure mainte-nance pump is needed.
Jockey pumps do not require a listing as fire protection equipment. Any pump that can produce the necessary pressure is acceptable. In general, jockey pumps are sized so that their flow is lower than that expected from the smallest orifice sprin-kler on the system, allowing for system pressure to fall and the fire pump to prop-erly activate. Although jockey pumps and their controllers do not require a listing, NFPA 20 includes a number of require-ments addressing their installation. As noted above, it needs to be confirmed that the jockey pump controller has a pressure-sensing line independent from that of the fire pump.
Test header and flow meter
Every fire pump installation needs to be provided with a testing means to ensure proper operation. At a mini-mum, arrangements must be provided to evaluate the pump at its rated condition as well as at its overload (150% of its rated capacity) condition. The means of testing must allow for the flow and dis-charge of significant quantities of water. NFPA 20 includes provisions for sizing the pipe used for testing. Such testing is conducted during the initial acceptance and/or commissioning of the fire pump installation, and on an annual basis in accordance with NFPA 25.
NFPA 20 allows for three different types of testing arrangements. These arrangements include the use of a dis-charge outlet such as a test header where water is discharged to atmosphere through connected hoses and nozzles with appropriate pressure and flow readings taken. The other two methods involve a metering device that is used to measure the flow produced by the fire pump. The metering device is installed on a pipe loop that is arranged so that the pump discharge is circulated back to the water supply tank, or arranged so that the pump discharge is circulated directly back to the suction line feeding the fire pump. This latter arrangement is referred to as closed-loop metering.
For closed-loop metering arrange-ments, NFPA 20 requires that an alternate means of measuring flow, such as through a test header, be provided. It is important to recognize that the alternate means of measuring flow must be installed down-stream of and in series with the flow meter. NFPA 25 includes provisions that fire pump metering devices be recalibrat-ed every 3 years. Locating the alternate means of measuring flow (test header) in the manner required by NFPA 20 facili-tates this calibration activity and better ensures an accurate assessment of fire pump performance.
As noted above, a test header can be installed without the use of a metering device and loop. Located on the discharge side of the pump, the test header must
22 Consulting-Specifying Engineer • MARCH 2015
be installed on an exterior wall of the pump room or pump house, or in another location outside the pump room so as to allow for adequate water discharge during testing. Hoses are connected to the test header during testing to allow for proper discharge and measurement of the water flow. Flow from the test header is usually measured by using a pitot gauge or other flow-measuring device placed in the flow stream. See NFPA 291 for further discussion on flow testing procedures. The pitot gauge registers a velocity pressure from the flow discharge, which can then be converted to a flow rate using a conversion formula or table.
The connection for the test header should be between the discharge check valve and the discharge control valve for the pump assembly. This allows the pump to be tested even when the control valve is closed, isolating the pump from the rest of the system.
The size of the pipe leading to the test header and the number of hose connections depends on the size of the pump. This is specifically addressed by NFPA 20. In the case of a 1250-gpm pump, a pipe at least 8-in. in diameter is required. The test header itself is to consist of six 2.5-in. hose valves and outlets. Where the length of pipe leading to the hose valve test header is more than 15-ft in length, the next larger pipe size as indicated in NFPA 20 is to be used.
Additionally, the pipe can be sized through the use of hydraulic calculations based on a total flow of 150% of the rated pump capacity. This hydraulic calculation is to include the friction loss for the total length of pipe plus any equiva-lent lengths of fittings, control valves, and hose valves, and elevation losses between the pump discharge flange and the hose valve outlets. This hydraulic calculation then needs to be verified by a flow test.
Pressure-relief device
A pressure-relief valve is a device on the discharge side of the fire pump that can be used to prevent overpressurization of the system. The pressure-relief valve operates when the pressure in the system reaches an unacceptably high level, such as may occur during an engine overspeed condition. Operation of the pressure-relief valve causes the pressure in the system to drop. One type of pressure-relief valve employs an adjustable
spring-Codes
&
Standards
A pressure-relief valve is a device on the
discharge side of the fire pump that can
be used to prevent overpressurization of
the system. It operates when the pressure
in the system reaches an unacceptably
high level, such as may occur during an
engine overspeed condition.
input #8 at www.csemag.com/information
800.231.2258
BALTIMORE, MD WWW.PRITCHARDBROWN.COM
• ISO-9001 Certified
• 70,000 ft2 of manufacturing space
• Strategically located for domestic and worldwide markets
• Over 65 years of experience • Turn-key systems available
• A vailable Certified IBC Seismic Compliance • Professional sales and engineering staff • High performance, maintenance free
materials
• Unparalleled customer service • Expertise in code compliance, extreme
sound attenuation and challenging applications
Like Us
loaded mechanism. When the pressure in the system reaches a predetermined level, the system pressure overcomes the force of the spring and forces the valve open. Another type of pressure-relief valve uses a pilot operated diaphragm which forces open the valve when the pressure in the system reaches a prede-termined level. With either one of these types of valves, a substantial discharge flow is expected and needs to be appro-priately accounted for.
NFPA 20 allows the use of pressure-relief valves only under two conditions. The first pertains to installations involv-ing a diesel engine pump driver. The second addresses installations involving variable speed pressure-limiting control-lers for either electric motors or diesel engines. Note that if pressure-relief valves are installed, NFPA 20 places a number of restrictions on the arrangement and sizing of the relief valve discharge depending on where the discharge is piped back to. In summary, NFPA 20 does not permit the use of pressure-relief valves as a means of limiting system pressure under normal system operation conditions, that is, as a substitute for higher pressure-rated sys-tem components.
For their broad range of applications, diesel engines are designed and built to operate over a range of speeds. For the purposes of driving a fire pump, a diesel engine should run at or near its rated speed so that the fire pump produces the desired flows and pressures. However, situations can occur in which the diesel engine oper-ates faster than its rated speed, creating an overspeed condition that produces exces-sive system pressures that could cause a catastrophic system failure or shortened life of system components.
From a hydraulics theory standpoint (pump affinity laws), a small increase in fire pump or driver speed creates a sub-stantially greater increase in system pres-sures, that is, the pressure developed is proportional to the square of the pumps’ rotational speed. Therefore, pumps oper-ating at speeds in excess of their rated speed can be a cause for concern. NFPA 20 includes a number of provisions that
address engine overspeed and system overpressurization.
Where the possibility for an overspeed condition of a diesel engine drive exists, and such an overspeed condition results in system pressure in excess of the pressure rating of the system components, which is
typically 175 psi. Specifically, NFPA 20 requires a pressure-relief valve in the dis-charge piping where a total of 121% of the net rated shutoff (churn) pressure plus the maximum static suction pressure, adjust-ed for elevation, exceadjust-eds the pressure for which the system components are rated.
Out of Sight... Peace of Mind
Automatic Smoke and Fire Curtains Open Up Design PossibilitiesColt automatic smoke and fire curtains from Bilco stay hidden until they’re needed. In the event of a fire, curtains automatically lower to aid emergency egress by protecting exit routes from smoke and heat. Products are equipped with an electric motor that holds the retracted curtain at ceiling level and unrolls the fabric automatically upon receiving a signal from a fire detection system.
For more information, log-on to www.bilco-colt.com
BLC925 CSE SmokeCurtain Ad.indd 1 2/13/15 8:59 AM
Codes
&
Standards
To facilitate avoidance of an engine overspeed and overpressure situation, NFPA 20 also requires the installation of an engine governor to regulate engine speed. The governor is required to be capable of limiting the maximum engine speed to 110% of its rated speed,
result-ing in a maximum system pressure of 121% of the fire pump churn pressure. However, failure of the governor would result in a more critical overspeed con-dition. As such, an overspeed shutdown device that senses the speed of the engine and shuts down the engine when it
oper-ates at a speed greater than 20% over its rated speed is also required. When the overspeed shutdown device operates, it sends a signal to the fire pump control-ler preventing automatic restarting of the engine until the situation is investigated. However, the pump can be manually restarted through the controller.
Another means of regulating engine speed and system overpressurization is through the use of a controller equipped with a variable speed pressure-limiting control. Such a device limits the total discharge pressure produced by the fire pump by reducing the pump driver speed, be it an electric motor or diesel engine. Prevention of overpressurization is therefore accomplished by altering the speed of the driver. However, where a variable speed pressure-limiting control-ler is used, and the maximum total dis-charge head adjusted for elevation with the pump operating at shutoff and rated speed exceeds the pressure rating of the system components, NFPA 20 requires the installation of a pressure-relief valve. Fire pump installations are often com-plex and require the coordination of vari-ous pieces of mechanical and electrical equipment, as well as the correct appli-cation of several installation standards and local regulations. Proper attention must be given to not just the sizing and connection of the more obvious compo-nents such as the fire pump, controller, and driver, but also the arrangement of the associated piping and attached devic-es. Without a well-coordinated effort addressing all the associated aspects of the installation, the life span of the fire pump equipment can be severely reduced and, more importantly, the fire pump cannot be expected to effectively oper-ate during its most critical time—when a fire occurs.
Milosh Puchovsky, PE, FSFPE, is profes-sor of practice in the department of fire protection engineering at Worcester Poly-technic Institute. He is president-elect of the Society of Fire Protection Engineers, and serves on a number of NFPA Techni-cal Committees including fire pumps and sprinkler system discharge criteria. ®
