FXB Engineering MEP www.fxbinc.com

HVAC in K-12 Projects

K-12 schools are becoming just as advanced as colleges and universities in design.

Meet challenging HVAC needs in K-12 buildings:

Induction chilled-beam design for HVAC installation is an option for a school that does not have cooling or mechanical ventilation. In conjunction with wall-mounted induction units, dedicated outdoor-air units can handle the total latent load of the building. This type of system allows the school to remove the existing unit ventilators and provide a system that is energy-efficient and improves indoor-air quality. Furthermore, it has minimal impact because the ductwork is being minimized.

Unique requirements in K-12 buildings:

Flexible-use spaces can vary in type of use and number of people (auditorium/cafeteria, gym/large event area, etc.). These nonspecific-use spaces create design options that must be carefully coordinated to meet expectations.

Schools and the learning environment have a critical focus on noise. The design must take into account solutions for sound attenuation. It is critical to mitigation noise without disrupting education.

Read more on this topic:

http://www.csemag.com/single-article/making-the-grade-with-k-12-projects-hvac/ba69a3aebb41c7efec94d191364e21ca.html

MRI

Mission Critical MEP/FP design for MRI Suites

Focus on the electrical, fire protection, and plumbing considerations when designing MRI suites.

Lighting 

An MRI scanner produces a radio frequency (RF) signal that must be protected from interference. Alternating current (ac) power has been known to result in RF interference and distortion of images. MRI room-lighting fixtures use direct current (dc) power. Lighting levels should be carefully reviewed.

RF shield
RF shields are typically thin sheets of copper foil, aluminum, or galvanized steel that cover floors, ceilings, doors, and windows in an MRI magnet room. Any penetrations into RF-shielded areas (HVAC, power, exhaust, plumbing, and piping) pass through RF filters or wave guides. Since ferromagnetic materials can interfere with MRI operations, all ductwork, hangers, and supports within the RF shield must be nonferrous.

Emergency power and UPS
Individual hospitals, along with the building code, determine the type of emergency power MRI equipment will need in the event of a power outage. Hospitals frequently use uninterrupted power supply (UPS) systems to maintain constant power to equipment during an outage or when transferring from one source to another. The UPS helps maintain power when switching to and from generator-backed power.

Plumbing and fire protection systems
MRI suites require unique plumbing and fire protection systems to meet the facility’s health and safety needs while also accommodating the equipment’s distinct specifications.

Plumbing
Designing plumbing systems around an MRI magnet room without interfering with sensitive equipment is particularly challenging. Water and drain lines must be installed in a way that will not interfere with the RF shield including passing through RF wave guides and dielectric breaks.

Fire protection
All sprinkler system components in MRI rooms must be constructed of nonferrous materials (copper, brass, and stainless steel are common). Careful consideration should be made for piping in adjacent spaces.

 

http://www.csemag.com/single-article/mepfp-design-for-mri-suites-part-two-design-considerations/0ea3e8a0b3f371481affa526cd28ade2.html

02/13/2017
FXB Engineering MEP www.fxbinc.com

Integrating commissioning, testing for fire alarm systems

System coordination includes commissioning and integrated testing of fire alarm systems using NFPA 3 and NFPA 4 as guidance.

  • Analyze NFPA 3 and NFPA 4, and how they relate to commissioning and testing fire protection systems.
  • Know the steps to commissioning and testing fire alarm systems.
  • Apply NFPA 3 and NFPA 4 in the design of a coordinated fire protection system.

Over the past decade, building design and construction has undergone a transformation of sorts. Gone are the days of individual standalone systems, designed in a vacuum by isolated design professionals from the various disciplines, with coordination limited to making sure equipment fit into the spaces allotted for it.

Today’s building designs emphasize system integration to achieve sustainability and efficiency goals. While this makes for a more stimulating design and construction effort, with professionals from all disciplines engaged to achieve much more lofty goals for the facility, it also requires foresight in the early stages of a project to develop a strategy and process to confirm that not only single systems are operating as intended, but also that system coordination is attained at the end of construction.

For fire protection systems, this process includes elements of both commissioning and integrated testing, as documented in NFPA 3: Recommended Practice for Commissioning of Fire Protection and Life Safety Systems and NFPA 4: Standard for Integrated Fire Protection and Life Safety System Testing.

Commissioning and integrated testing are two different concepts, though both are needed to properly evaluate the operation of a fire alarm system and confirm that it interacts properly with other systems. In practice, the two are not necessarily inclusive. A commissioning authority (CxA) is responsible for the commissioning of individual systems, such as the fire alarm system, and does not evaluate interaction with other systems. An integrated testing agent (ITa) plans and executes the integrated testing of interconnected systems. The CxA and the ITa are not required to be the same entity.

However, a company or person who has qualifications of both fire alarm commissioning and integrated testing can provide both services, which is a good practice that also increases efficiencies. For the sake of simplicity in this article, the CxA and the ITa are considered to be the same person or company-one that is qualified to serve both roles simultaneously.

Commissioning has many definitions. The focus is on the commissioning and integrated testing of fire alarm systems, so the definition from NFPA 3 seems most appropriate:

A systematic process that provides documented confirmation that building systems function according to the intended design criteria set forth in the project documents and satisfy the owner’s operational needs, including compliance with applicable laws, regulations, codes, and standards.

This definition summarizes the intent of commissioning efforts while highlighting the overall intent of the process: the assessment and documentation that systems operate as intended by design and meet owner’s needs as well as applicable code and standards. It is very important to note the distinction that commissioning determines that systems meet design criteria and code requirements as well as satisfy owner needs. CxAs are ultimately working on behalf of the owner’s best interest and need to keep that fact in mind throughout the project.

The fire alarm system hub 

Building commissioning efforts are far-ranging, with evaluations for all building systems as well as their interaction with other systems to meet facility objectives. As a result, fire alarm commissioning represents a small portion of the overall whole. Despite its relative scope in relation to other systems, however, the fire alarm system is critical to the building operation and typically requires coordination with many other facets of the building commissioning. In most buildings, the fire alarm system acts as a central hub of information gathering and distribution, especially with respect to other fire protection and life safety systems. Consider for a moment some of the building systems with which the fire alarm system may communicate, depending on the type and scale of the building (see Figure 1):

  • Alarm notification
  • Building management systems (BMS)
  • Elevator systems
  • Emergency communication/notification systems
  • Emergency power
  • Fire suppression systems
  • Gas detection
  • HVAC systems
  • Security and access control systems
  • Smoke control systems.

This is not an exhaustive list, as buildings with special hazards or occupancies will have additional systems that may interface with the fire alarm system. Process equipment in industrial facilities may coordinate shutdown procedures with the fire alarm systems under specific scenarios. Assembly spaces, such as theaters and performance halls, may interface with the fire alarm system to terminate audio in the room and bring up house lighting upon certain circumstances to provide orderly evacuation.

The point is that although the fire alarm system is a single system within a building, its interaction with other systems is now extensive. It is no longer a control panel at the entrance to the building, communicating with alarm-activation devices, supervising a few sprinkler system control valves, and activating occupant-notification appliances. Mapping and confirming the flow of information to and from the fire alarm system and identifying its interactions with other systems can be a complex and daunting undertaking. The CxA for the fire alarm system must, therefore, not only understand that system, but also be able to recognize and comprehend the extent and intent of the interplay with other systems under all scenarios and then capture it all in the commissioning effort.

Fire alarm commissioning/testing 

In an ideal world, the fire alarm commissioning and integrated testing effort would be established and coordinated at the start of the design of a project and follow the systematic approach documented in NFPA 3 and NFPA 4. That approach is summarized below:

  1. Review and assist in final development of the owner’s project requirements (OPR) document, which establishes the design objectives and goals of the systems.
  2. Review and provide input on the basis of design (BOD) report, which records the specific design strategy for each system.
  3. Perform design reviews throughout the project to evaluate the design and sequence of operations against the BOD.
  4. Develop a commissioning plan, which is a living document detailing the commissioning process and tests required as part of the commissioning. The commissioning plan should include a commissioning schedule, which is evaluated and updated periodically as the project progresses.
  5. Develop an integrated test plan, which identifies the specific tests that will be conducted for each system, including the interaction of systems as required to confirm that the building will operate as intended and meet the objectives.
  6. Review and verify that shop drawing/equipment system submittals are in conformance with the BOD.
  7. Perform regular inspections during installation to verify compliance with design and approved system submittal documents.
  8. Perform system testing in accordance with the commissioning plan and prepare documentation. Follow-up testing and inspections may be necessary to
  9. Prepare the commissioning report, which is a comprehensive database of all information developed during the full commissioning process.
  10. Perform system testing in accordance with the integrated testing plan and prepare documentation. Follow-up testing and inspections may be necessary to verify that required modifications are made and the system operates as required.
  11. Prepare the integrated test report, which outlines the test performed and the results of those tests. The integrated test report also provides the recommended periodic integrated test frequency based on their understanding and the complexity of the system.

Unfortunately, we often do not live and work in an ideal world. Currently, fire alarm commissioning rarely follows the NFPA systematic approach for a number of reasons.

The simplest reason relates to a common misunderstanding of the intended breadth of commissioning and integrated testing. Despite the consistently growing trend toward “commissioning” a building, too often system acceptance testing with the authority having jurisdiction (AHJ) is still erroneously equated to it, especially for fire protection systems. The project stakeholders simply expect that system acceptance testing performed in accordance with the system design and installation standard will suffice.

For fire protection systems, the requirement for testing of the system before receiving approval from the AHJ is a disadvantage. For many other systems, commissioning represents the inauguration of a means of evaluating and testing system performance. Commissioning means starting with a clean slate for these systems. Having an evaluation method already in place for fire alarm systems can make it harder to alter existing preconceptions to reflect the true mission of commissioning and integrated testing.

Another reason for not following this systemic approach is cost. Comprehensive commissioning and testing in any form represent a greater cost to owners than in the past. While it can be argued that the upfront cost of commissioning is defrayed by verifying that the building is operating properly and efficiently, it can still represent sticker shock to an owner. With energy efficiency and sustainability representing the vanguard of the commissioning movement, it is easy to dismiss other systems that don’t directly or noticeably contribute to these goals. The other reality in today’s marketplace is that the fire protection systems are rarely properly reviewed, coordinated, designed, and installed with an eye toward both code compliance and the best interest of the owner. The commissioning process fills that void.

Many owners or end users don’t recognize the importance of the fire alarm system and its interaction with various other systems, thus it is treated as a single system that can be easily commissioned at the end of a project. This can lead to one of two scenarios:

  1. The fire alarm system is commissioned as a standalone system and its integration with other systems is never evaluated.
  2. Recognition of its role as a central hub for several systems occurs late in design or into construction, and an abbreviated commissioning process is administered.

Neither scenario is beneficial to creating a fully integrated and functional building, though scenario two at least offers the potential to achieve commissioning goals at the end of the project. In fact, the second scenario probably represents the current standard for commissioning a fire alarm system, at least based on the bulk of our experience. Initiating commissioning efforts near the end of design or during the construction phase of a project is normal, and it comes with challenges and the potential for significant discomfort for both the design and construction teams. While the systematic approach of the NFPA documents may appear to be excessive to some, it can alleviate a lot of issues and apprehension at the end of a project.

http://www.csemag.com/single-article/integrating-commissioning-testing-for-fire-alarm-systems/a52fdd82ef05063868a3209b22c3c8a3.html

01/30/2017
FXB Engineering MEP www.fxbinc.com

Why Covers are Removed for IR Surveys

By Lawrence H. Ulmer, IV
FXB Engineering

The attached images are from survey at a typical multi-tenant office building.  No visible signs of a problem on this panel with cover on and door open.  This is why we remove covers during IR surveys.

(3) identical 70A breakers feeding RTU’s

Breaker at top looked normal for no load. Slight heat differential between the two phases but nothing significant.

Breaker in middle was showing heat rise on conductors typical of load, but no measurable load on meter.  This is a result from heat building up in the breaker.

Breaker on bottom had even load on conductors, but (1) conductor significantly hotter than the other.  Either a termination issue or the breaker is failing internally (or both).

E.C. touched conductor while getting load, arcing started to appear behind middle breaker.You can see where the arcing was occurring on the other images where the breaker bolted to bus.   Looks like a bright copper weld spot surrounding by carbon deposits.

We left the room, called the property manager to get approval to de-energize the circuit and remove the breakers.   They lost the operation of (1) HVAC unit and can now schedule repair.

This was old federal pacific equipment that has been poorly maintained.   If left unaddressed they would have lost at a minimum the entire panel if the breaker feeding it operated properly.  Most likely increased physical damage to other breakers in the panel and a fault condition that could have tripped a breaker upstream somewhere dropping more load.     This panel also just so happened to be sitting directly above the desk of the facility maintenance personnel, less than 3’ from where his head would be while sitting at the desk.  Code violation but common occurrence in old buildings.

This incident being detected early just saved the management company thousands of dollars (possibly >$10k)  and potentially prevented personal injury (+$50k easy in insurance deductible).

Editor: Lawrence earns 6 ITC certification renewal credits for his story.

 

FXB Engineering MEP www.fxbinc.com

MEP Engineering News Recap

1. Previewing NEC 2017 changes

The current version of NFPA 70: National Electrical Code (NEC) is the 2014 edition. Though this version has not been adopted in all jurisdictions, this article reviews a project that is being designed to meet the 2014 code. A few key updates to the NEC in 2017 and their potential impacts to future designs are also highlighted.

2. Calculating economics of HVAC systems

Codes and standards, equipment efficiencies, energy modeling, commissioning, energy-conservation incentive programs, and lifecycle cost analysis all play into determining the economics of HVAC systems. Included are key aspects a mechanical engineer may need to consider when specifying HVAC systems into new or existing buildings, with a focus on the economic analysis provided to the client.

3. Assessing replacement of electrical systems

Replacement of electrical systems is a study of economics and risk. Factors including age, safety, reliability, efficiency, and energy costs must be weighed in conjunction with replacement costs and liability risk to formulate and prioritize upgrade plans. A comprehensive cost-benefit analysis study for each electrical subsystem will allow facilities to plan short-term and long-term expenditures for maintenance and upgrade programs for prudent facility reinvestments, replacements, and growth.

4. Understanding the fan-efficiency rules

Fan efficiency is critical in HVAC and process air systems. The new proposed Department of Energy standard will drive changes in how engineers design air systems to minimize fan energy.

5. Why engineers should use a whole-system approach for design and construction

Using a whole-system approach to specifying equipment can lead to many benefits, such as improving the building’s energy efficiency.

 

http://www.csemag.com/single-article/top-5-consulting-specifying-engineer-articles-december-26-january-1-nec-2017-changes-economics-of-hvac-systems-assessing-replacement-electrical-systems-more/4d49e5cdddc725c699cb00be910105b3.html

FXB Engineering MEP www.fxbinc.com

Understanding the fan-efficiency rules

Fan efficiency is critical in HVAC and process air systems. The new proposed Department of Energy standard will drive changes in how engineers design air systems to minimize fan energy.

 

Fans consume about 18% of electricity purchased in commercial and industrial buildings. Most commercial fans also consume their initial cost in energy expense in less than 1 year. While fan efficiency varies with aerodynamic shape, under-sizing fans to reduce first cost has a stronger negative influence on fan efficiency. That is why the U.S. Department of Energy (DOE) is considering a novel approach, which would reward rightsizing fans in addition to improved aerodynamic design.

Read more