Speaking Out on 9/11 and Other Topics Thanks for the thoughts recalling Sept 11 (Editor's Viewpoint CSE 09/02 p. 7). I share your feeling of a renewed perspective as we must look at what we can and should do to make this a better place for us, our children and beyond. I also think we all need some more of that "Catholic guilt" of aspiring to live and conduct ourselves by very lofty standards.
Speaking Out on 9/11 and Other Topics
Thanks for the thoughts recalling Sept 11 (Editor's Viewpoint CSE 09/02 p. 7 ). I share your feeling of a renewed perspective as we must look at what we can and should do to make this a better place for us, our children and beyond. I also think we all need some more of that "Catholic guilt" of aspiring to live and conduct ourselves by very lofty standards. I grew up with it as well and even now it helps me think about what impact my role and actions will make. But it's a difficult thing to share and something that makes me appreciate the nuns who were so natural in instilling those values in children.
Thanks again for reminding us that we must think. Thanks also for reminding us that we must not take ourselves so seriously. Your wife's aunt seems like a great lady and teacher.
Pat Banse, P.E., SSR Inc., Houston
Exercise your freedom
The failure of architects and engineers to get more involved in civic and governmental affairs is going to result in more national tragedies like 9/11. Congress and even the White House are filled with personalities hostile to liberty, free markets and competitive capitalism.
Anybody who has finally had enough of this thrust into tyranny should visit www.thenewamerican.com and learn some helpful facts.
John K. Carter, P.E., Camarillo, Calif.
Regarding the M/E Roundtable: "Tuning out Harmonics" ( CSE 09/02 p.23 ), I appreciated the well-made comments from both the manufacturers and the consultants, and their perspectives on treating harmonics in three- and four-wire, three-phase systems. However, the subject of energy loss due to harmonics was not discussed, particularly the continued application of K-rated transformers in spite of their inability to treat harmonics and their inherent energy inefficiencies under non-linear loading conditions.
Transformer selection and application present a number of issues alone. The standards—or lack thereof—that influence the selection process are poorly understood by many engineers and CSE would be well served to expound on the following:
The inability of K-rated transformers to provide power quality or energy efficiency improvement. In fact, they are detrimental when feeding non-linear loads.
The failure of NEMA TP-1 guidelines and programs like Energy Star to apply beyond lightly loaded transformers that feed linear loads. While well-intentioned in concept, the effectiveness of such guidelines is negated since non-linear loads—representative of the real world—are exempt.
The fact that transformers that offer both energy savings and enhanced power quality have markedly lower life-cycle costs vs. conventional or K-rated transformers that offer significant recurring savings throughout their lives.
Myths which abound throughout the industry concerning the use of low temperature rise transformers. Misapplication of the same actually inflicts a penalty on a design's energy budget.
Richard E. Draper, P.E., Powersmiths Corp., Irving, Texas
What about plastic?
Regarding "By the Book," ( CSE 08/02 p. 46) on flammable liquid room storage, I have two comments: First, the paragraph dealing with water on fires in liquids with greater than 200°F makes no sense as the temperature of any flammable liquid fire is well over the boiling point of water. Water absorbs heat from fire by the energy absorbed when it turns to steam.
Second, there is no mention of the composition of the storage containers. Plastic containers are a much greater fire hazard than metal containers.
Frank Ward, FM Global
"By the Book" Authors Jonathan Eisenberg and Eric Cote respond:
Comment No. 1: In the paragraph on high flashpoint liquids, the intent was to recommend an alternative to water as a suppression agent. For liquids with a flashpoint much higher than the boiling point of water, the heat release rate (HRR) will increase quickly—and briefly—when water is applied. We agree that this is also true for low flashpoint liquids, but to a lesser degree. The increase in HRR for high flashpoint liquids—when water is applied—could be significant enough to ignite nearby combustible materials.
Comment No. 2: Considerations are different for plastic vs. metal containers, and are addressed in NFPA 30, Flammable and Combustible Liquids Code (2000 Edition), specifically, section 4.8, which contains sprinkler densities and design areas for different sizes and types of containers.