Combination Antibiotic Therapy Lowers Mortality among Severely Ill Patients with Pneumococcal
Combination Antibiotic Therapy Lowers
Mortality among Severely Ill Patients
with Pneumococcal Bacteremia
Larry M.Baddour,Victor L.Yu,Keith P.Klugman,Charles Feldman,Ake Ortqvist,Jordi Rello,Arthur J.Morris,
Carlos M.Luna,David R.Snydman,Wen Chien Ko,M.Bernadete F.Chedid,David S.Hui,Antoine Andremont, Christine C. C.Chiou,and the International Pneumococcal Study Group
Mayo Clinic,Rochester,New York;Division of Infectious Disease,University of Pittsburgh,Pittsburgh,Pennsylvania;Department of International Health,Rollins School of Public Health,Emory University,Atlanta,Georgia;Respiratory and Meningeal Pathogens Research Unit and Pulmonary Division,Department of Medicine,Johannesburg Hospital,University of the Witwatersrand/Medical Research Council/National Health Laboratory Service,Johannesburg,South Africa;Department of Communicable Disease Control and Prevention,Karolinska Institute,Karolinska Hospital, Stockholm,Sweden;University Hospital Joan XXIII,University Rovira and Virgili,Tarragona,Spain;Clinical Microbiology Laboratory,Auckland Hospital,Auckland,New Zealand;Division of Pulmonary Medicine,Hospital de Clinicas,Universidad de Buenos Aires,Buenos Aires,Argentina; Division of Geographic Medicine and Infectious Diseases,Tufts-New England Medical Center,Tufts University School of Medicine,Boston, Massachusetts;Department of Medicine and Therapeutics,Chinese University of Hong Kong,Prince of Wales Hospital,Shatin,Hong Kong; Division of Infectious Diseases,National Cheng Kung University Hospital,Tainan,and Department of Pediatrics,Veterans General Hospital-Kaohsiung,National Yang Ming University,Taipei,Taiwan;Postgraduate Program in Pulmonology,Federal University of Rio Grande do Sul, Hospital de Clinicas de Porto Alegre,Porto Alegre,Brazil;Laboratory of Bacteriology,Ho?pital Bichat-Claude Bernard,Assistance Publique
Ho?pitaux de Paris,Paris,France
Retrospective studies have suggested that combination antibiotic therapy for severe bacteremic pneumococcal pneumonia may re-duce mortality.We assessed this issue in a prospective,multicenter, international observational study of844adult patients with bacter-emia due to Streptococcus pneumoniae.The effect of combination antibiotic therapy versus monotherapy on mortality was examined by univariate analyses and by logistic regression models.The14-day mortality was not significantly different for the two groups. However,among critically ill patients,combination antibiotic ther-apy was associated with lower14-day mortality(23.4versus55.3%, (Received in original form November19,2003;accepted in final form May21,2004) International Pneumococcal Study Group:Argentina:Hospital de Clinicas:Carlos M.Luna,M.D.(PI),Ricardo Mosquera,M.D.,Carmen de Mier,Ph.D.,Angela Famiglietti,Ph.D.,Carlos Vay,Ph.D.;Hospital Santmarina:Jorge Gentile,M.D., Monica Sparo,Ph.D.Brazil:Hospital de Clinicas de Porto Alegre:Maria Bernadete F.Chedid,M.D.(PI),Sergio Menna Barreto,M.D.,Afonso L.Barth,Ph.D.;Santa Casa de Misericordia de Porto Alegre:Cicero Dias,Ph.D.;Hospital N.S.da Concei-cao:Breno Riegel dos Santos,M.D.France:Hospital Bichat-Claude Bernard:An-toine Andremont,M.D.(PI);Karine Grenet,Pharm.D.,Hyam Mounieme,M.D. Hong Kong:Chinese University of Hong Kong:David Hui,M.D.(PI),Margaret Ip, M.D.,Donald Lyon,M.D.New Zealand:Auckland Hospital:Arthur J.Morris,M.D. (PI),Sally A.Roberts,M.B.,Ch.B.,Dragana Drinkovic,M.D.,Susan L.Taylor,M.B., Ch.B.South Africa:Johannesburg Hospital,Johannesburg:Charles Feldman,M.B., Ph.D.(PI),Keith P.Klugman,M.D.(Co-PI);Anne von Gottberg,M.B.,Xoliswa Poswa,M.B.,Rajen Morar,M.B.Spain:University Hospital Joan XXIII and Corpo-racio Sanitaria Parc Tauli,University Rovira and Virgili,Tarragona:J.Rello,M.D. (PI),Miquel Gallego,M.D.,M.Lujan,M.D.,Emili Diaz,M.D.,Dolors Mariscal, M.D.,Dionisia Fontanals,Pharm.D.,Jose M.Santamaria,M.D.Sweden:Karolinska Hospital,Stockholm:Ake Ortqvist,M.D.(PI),:Margareta Rylander,M.D.,Ph.D. Taiwan:Tri-Service General Hospital,Taipei:Feng-Yee Chang,M.D.(PI);National Cheng Kung University Hospital,Tainan:Wen-Chien Ko,M.D.(PI),St.Martin De Porres Hospital:Wen-Pin Wu,Chia Yi.United States:New England Medical Center, Boston,MA:David R.Snydman,(PI),Laurie Barefoot,R.N.,Laura McDermott. National Naval Medical Center,Bethesda,Maryland:David L.Blazes,M.D.,Greg-ory Marin,M.D.;University of Tennessee Medical Center:Knoxville,Tennessee: Larry M.Baddour,M.D.(PI):Mandana Mobasseri;University of Pittsburgh and Veterans Affairs Medical Center,Pittsburgh,PA:Victor L.Yu,M.D.(PI),Dong Hoon Daniel Kim,M.D.,John D.Rihs.
Correspondence and requests for reprints should be addressed to Victor L.Yu,M.D., VA Medical Center,Infectious Disease Section,University Drive C,Pittsburgh,PA 15240.E-mail:vly?@https://www.sodocs.net/doc/149556191.html,
Am J Respir Crit Care Med Vol170.pp440–444,2004
Originally Published in Press as DOI:10.1164/rccm.200311-1578OC on June7,2004 Internet address:https://www.sodocs.net/doc/149556191.html, p?0.0015).This improvement in survival was independent of country of origin,intensive care unit support,class of antibiotics,or in vitro activity of the antibiotics https://www.sodocs.net/doc/149556191.html,bination antibiotic therapy improved survival among critically ill patients with bacter-emic pneumococcal illness.
Keywords:bacteremia;community-acquired pneumonia;Streptococcus pneumoniae
Does combination antibiotic therapy improve survival among patients with severe community-acquired pneumonia?As em-phasized in one commentary(1),treatment guidelines(2–5)from several authoritative groups support the use of empiric combina-tion antibiotic regimens for patients with severe pneumonia. Combination regimens ensure coverage of Legionella species and“typical”bacterial pathogens.Streptococcus pneumoniae re-mains the most common cause of death among patients with severe pneumonia and the prognosis is worse for those who develop complicating bacteremia.
Data from three retrospective analyses of patients with bac-teremic pneumococcal pneumonia(6–8)suggest that combination antibiotic therapy is associated with reduced mortality as compared with that seen among those who receive only antibiotic monother-apy.In one of the studies(7),adults with severe bacteremic pneu-mococcal pneumonia had a signi?cantly greater risk of dying if they received monotherapy rather than combination antibiotic ther-apy on the?rst day of hospital admission.The remaining two studies(6,8)focused on the addition of a macrolide to?-lactam antibiotic treatment and also demonstrated improved survival among those who received combination antibiotic therapy.
The authors of the three studies and of associated editorials (1,9)acknowledged the potential biases and confounding factors that characterize retrospectively conducted treatment assess-ments.We therefore provide the?ndings of a prospectively conducted,observational,international investigation that exam-ines the role,if any,of combination antibiotic therapy in reducing the mortality of bacteremic pneumococcal illness.To our knowl-edge,this work represents the?rst prospective evaluation of the impact of combination therapy on mortality.
METHODS
Details of this observational study have been presented elsewhere(10), so the following represents an abbreviated version.Between December1,
Baddour,Yu,Klugman,et al.:Combination Antibiotics for Pneumococcal Bacteremia441
1998and December31,2000,844consecutive adults with pneumococcal bacteremia were enrolled in21hospitals in10countries on6continents. Patients were monitored for at least14days after the?rst positive blood culture or longer if the patient remained hospitalized.
All patients15years of age and older who had at least one blood culture positive for S.pneumoniae during the25-month study period were included.Patients were classi?ed as“elderly”if they were65years of age or older;“immunosuppressed”if they had human immunode?ciency virus infection,hematologic malignancy,or an autoimmune disorder,had received either organ or bone marrow transplant or cancer chemotherapy within4weeks of pneumococcal bacteremia,or had undergone prior splenectomy;and/or as having“underlying chronic disease”if they had heart,lung,liver,or renal disease or diabetes mellitus.Patients were de?ned as critically ill as calculated by a Pitt bacteremia score greater than4,as described previously(10,11).The APACHE(Acute Physiology and Chronic Health Evaluation System)II score was calculated for pa-tients admitted directly to the intensive care unit(ICU).
Antibiotic therapy was eligible for analysis if the total daily dose of an agent was at least the minimum dose recommended for treatment of systemic infection.Patients who did not receive antibiotic(s)on the day of admission were excluded.Monotherapy was de?ned as receipt of the same single antibiotic within the?rst2days of obtaining a positive blood culture;likewise,combination therapy was de?ned as receipt of the same two antibiotics within the?rst2days of positive blood culture. Patients who received no antibiotic therapy or delayed treatment(more than24hours after admission),or had no consistent antibiotic regimen (e.g.,1day of monotherapy plus1day of combination therapy)over the initial2days of admission were excluded.
Differences in categorical variables were calculated by?2test with the Yate correction or Fisher exact test.The Kaplan–Meier product limit method was used to construct survival curves for patients receiving combi-nation and monotherapy regimens.The patients were strati?ed by severity of illness and the survival curves were compared using the Mantel–Cox test(12).A logistic model was used to adjust for additional risk factors in evaluation of the impact of combination therapy on14-day mortality. Factors associated with increased mortality by univariate analysis were entered into the model in addition to receipt of combination therapy. RESULTS
Eight hundred forty-four consecutive cases of pneumococcal bac-teremia were enrolled.Patients were excluded if they received no antibiotic therapy(43);received no antibiotic therapy on Day 2(30);received delayed(more than24hours after admission) antibiotic therapy(23);underwent an inconsistent regimen(e.g., 1day of monotherapy plus1day of combination therapy)(86); or underwent different monotherapy or combination therapy regimens on Day1and Day2(70).The remaining592patients were available for analyses of monotherapy versus combination therapy.
As we have reported previously,16.5%of patients(139of 844)died by Day14(10).The risk of death was almost eightfold greater for critically ill patients compared with patients who were less ill at hospital admission(54.6versus7.3%,p?0.0001). The14-day mortality was not signi?cantly different for all pa-tients receiving combination versus monotherapy(10.4versus 11.5%,p?NS).Among critically ill patients(n?94),however, combination antibiotic therapy was associated with lower mor-tality(14-day mortality,23.4versus55.3%,p?0.0015)(Figure 1).The most common monotherapy regimens prescribed for the critically ill patients were?-lactam agents(43,with25receiving a third-generation cephalosporin),azithromycin(2),cipro?oxacin (1),and clindamycin(1).The most frequent combination therapies prescribed were?-lactam/macrolide(14),vancomycin/?-lactam (12),?-lactam/aminoglycoside(7),vancomycin/other antibiotic(4),?-lactam/quinolone(4),double?-lactam therapy(2),?-lactam/ chloramphenicol(2),?-lactam/trimethoprim-sulfamethoxazole(1), and clindamycin/quinolone(1).
This difference in mortality remained signi?cant when ana-lyzed according to in vitro activity,as de?ned by the
National Figure1.(A and B)Survival graphs stratified by severity of illness.(A) Kaplan–Meier survival plot for patients who were not critically ill as defined by the Pitt bacteremia score.(B)Kaplan–Meier survival plot for 94patients who were critically ill as defined by the Pitt bacteremia score. Combination therapy was superior to monotherapy among critically ill patients(p?0.008,Mantel Cox).
Committee for Clinical Laboratory Standards(NCCLS),of the monotherapy or combination drug therapy.Penicillin-susceptible isolates(minimal inhibitory concentration,less than0.12?g/ml) and penicillin-nonsusceptible isolates(minimal inhibitory con-centration,0.12?g/ml or more)were distributed equally between the two groups(Table1).One hundred percent(94of94)and 98.9%(93of94)were susceptible to ceftriaxone and cefotaxime, respectively,using recent NCCLS breakpoints(13).When all treatments were active in vitro,mortality for combination versus monotherapy was19.4versus60%(p?0.0006),respectively. When at least one of the drugs of the combination therapy was active in vitro,mortality for combination therapy versus monotherapy was18.2versus60%(p?0.0003),respectively. No patient received combination therapy in which both antibiot-ics were inactive in vitro.The demographics for the monotherapy versus combination therapy groups were comparable except for human immunode?ciency virus therapy and mechanical ventilation (Table1).When adjusted for mechanical ventilation and human immunode?ciency virus positivity by multivariate analysis,combi-nation therapy remained a signi?cant factor in decreasing mortality (Table2).Severity of illness as measured by APACHE II or Pitt bacteremia score was essentially identical for the two groups.
One hundred twelve patients were admitted to the ICU on admission;note that not all were critically ill,and therefore the number is not94.The severity of illness was nearly identical in patients receiving combination therapy and monotherapy(mean Pitt bacteremia score,5.0versus5.5,respectively;APACHE II score,19.0versus19.2,respectively).Nevertheless,the patients
442AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL1702004
TABLE 1.DEMOGRAPHICS OF THE TWO STUDY GROUPS
OF SEVERELY ILL*PATIENTS
Combination Monotherapy Parameter(n?47)(n?47)p Value Age,?65yr20.0%16.1%NS Hospital acquired8.5%10.6%NS Community acquired91.5%89.4%NS Underlying chronic disease?48.8%34.1%NS Immunosuppressed?47.8%32.6%NS HIV11.4%37.0%0.01 Neutropenic19.1%11.1%NS Asplenia 2.1% 2.1%NS COPD20%11.6%NS Penicillin susceptibility in vitro?
Resistant13.0%13.9%NS Intermediate17.4%16.3%NS Sensitive69.6%69.8%NS High-level resistance12.8%12.8%NS Mechanical ventilation78.7%51.1%0.01 APACHE score,mean?SE19?1.119?2NS Pitt bacteremia score,
mean?SE 6.6?0.3 6.3?0.3NS Definition of abbreviations:APACHE?Acute Physiology and Chronic Health Evaluation System;COPD?chronic obstructive pulmonary disease;HIV?human immunodeficiency virus.
*Severely ill,defined as Pitt bacteremia score?4.
?Immunosuppressed and underlying chronic disease are defined in M ETHODS.?Penicillin susceptibility in vitro:high-level resistance,minimal inhibitory con-centration(MIC)?3?g/ml;resistant,MICу2?g/ml;intermediate,MIC?0.12–1?g/ml;susceptible,MIC?0.12?g/ml.
receiving combination therapy had a signi?cantly lower14-day mortality than those receiving monotherapy(8.2versus23.1%, p?0.03).The superiority of combination therapy was also evident in various logistic regression models of ICU patients (data not shown).
The combination regimens were further examined to deter-mine whether the difference seen in mortality rates between the two groups of critically ill patients was due to a speci?c antibiotic or combination of antibiotics.This was not the case;when com-pared with monotherapy,mortality rates were lower for antibiotic combinations that included?-lactams(26.8%,p?0.007),vanco-mycin(6.3%,p?0.0006),or macrolides(14.3%,p?0.007). TABLE 2.LOGISTIC REGRESSION MODELS ASSESSING COMBINATION THERAPY
Survival Odds Ratio SE p Value95%CI Adjusted for HIV Status*
Combination 3.2 1.70.028 1.1–9.2 HIV0.090.060.0000.02–0.3 Adjusted for mechanical
ventilation?
Combination 2.9 1.50.04 1.1–7.7 Mechanical ventilation8.1 4.20.0001 3.0–2.2 Definition of abbreviations:CI?confidence interval;HIV?human immunodefi-ciency virus.
Variables that were evaluated in the logistic models were those that were significant in univariate analysis at the0.05level.The end point was survival at Day14.There were no significant interactions between the main effects in the models.Main effects did not show collinearity.The models were tested for good-ness of fit using the Pearson?2and the deviance?2.The standard deviance residuals were also tested for normality using the Shapiro–Wilk test.
*Combination antibiotic therapy had a significant positive association with survival even when adjusted for HIV status.
?Combination antibiotic therapy had a significant positive association with survival even when adjusted for mechanical ventilation.Numbers were too small to allow analysis of?uoroquinolones, aminoglycosides,and clindamycin.The impact on mortality for combination regimens was most evident when a second antibiotic was added to a?-lactam agent(the most commonly prescribed therapy for both groups).The mortality was26.8%(11of41) for those who received a?-lactam–containing combination regi-men as compared with58.4%(24of41)(p?0.004)for those who received a?-lactam as monotherapy.Because no patient received vancomycin as monotherapy and only two patients were given a macrolide as monotherapy in the critically ill group,no comparisons were made between combination versus monother-apy when either vancomycin or a macrolide was included in both treatment arms.
Varying durations of receipt of antibiotics have been used to de?ne combination therapy versus monotherapy in the litera-ture;our analyses assessed mortality with a2-day duration(see Methods for de?nition).Thus,we also analyzed the14-day mortality for patients receiving antibiotic therapy for1day(as de?ned by Waterer and coworkers[7])(n?775patients)as well as3days(n?510patients).Mortality was signi?cantly lower for combination therapy compared with monotherapy if the1-day duration was used(43%[31of72]versus60%[45of 75],p?0.026)or a3-day duration was used(11.4%[4of35] versus42.8%[12of28],p?0.008).
When therapy was analyzed by country of origin,insuf?cient statistical power existed for analysis for some individual coun-tries;when the number of cases exceeded12in a country,there was a clear-cut trend for superiority of combination therapy in those countries.When adjusted for country,patients receiving combination therapy remained a signi?cant factor in decreasing mortality in logistic regression models(data not shown). DISCUSSION
Findings from this large,prospective,international investigation suggest that the administration of combination antibiotic therapy results in increased survival among critically ill patients with pneumococcal bacteremia(Figures1A and1B).There was a more than twofold increase in survival among recipients of com-bination antibiotic therapy as compared with that for recipients of monotherapy regimens.Receipt of combination therapy and mechanical ventilation were signi?cant factors in improving out-come by both univariate and multivariate analyses.The?ndings of signi?cant increases in mortality for both critically ill and elderly patients(10),two well recognized subgroups at increased risk of dying,bolster the validity of the study’s principal observa-tion that outcome is improved with combination antibiotic ther-apy for severely ill patients with pneumococcal bacteremia.
The in vitro antibiotic resistance for monotherapy or one of the two antibiotics in the combination regimen did not signi?-cantly affect mortality.The clinical impact of in vitro resistance as de?ned by current NCCLS guidelines has been described in an earlier report derived from this study in which penicillin and third-generation cephalosporin resistance in vitro was not a risk factor for mortality(10).Speci?cally,outcomes in both critically ill and noncritically ill patients were not in?uenced by whether they received concordant or discordant therapy based on pneu-mococcal in vitro susceptibility results.
There are several strengths of the current investigation that are not shared by the three previous retrospectively conducted studies(6–8)that examined the impact of combination therapy on mortality.Our study enrolled844consecutive patients who were prospectively enrolled from21hospitals in10countries of6 continents between December1,1998and January2001.In con-trast,the three previously published studies(6–8)were retrospec-tively conducted and enrolled patients from three geographically
Baddour,Yu,Klugman,et al.:Combination Antibiotics for Pneumococcal Bacteremia443
con?ned areas,two(6,7)of which were in the United States and one in Spain(8).The applicability of?ndings from these earlier investigations may be limited because case-fatality rates of community-acquired bacteremic pneumococcal illness differ greatly by geographic locale(14).The numbers of patients in-cluded in these three trials were fewer than that enrolled in our study.Our patient enrollment was performed more recently in the era of increasing antibiotic resistance,whereas the other studies were performed in1978,1991,and1996,respectively.A retrospective analysis of a hospital claims-made database,which included more than44,000patients seen between1997and1999 for community-acquired pneumonia,also found that combina-tion antibiotic therapy reduced mortality(15).
It should be noted that the de?nition of combination antibi-otic therapy was only1day in the Waterer and coworkers study (7)and was not speci?ed in the other two retrospective studies (6,8).Although our analyses given in the Results applied to the2-day de?nition of duration of antibiotic therapy,we also assessed the impact of combination therapy1and3days after admission because our previous study showed that64.5%of these patients died not more than72hours after blood culture had been obtained(10).Mortality for combination therapy re-mained signi?cantly lower for all durations used(Results).We evaluated quality of support services other than antibiotics by analyzing a subgroup of patients admitted to the ICU.Again, combination therapy led to signi?cantly lower mortality than monotherapy.Finally,mortality was signi?cantly lower for com-bination therapy versus monotherapy when controlled for ICU admission and country of origin.
There were limitations to our study.First,as with other stud-ies exploring this issue,these results were not from a randomized controlled study.However,the combination and monotherapy groups were generally comparable(Table1),and severity of illness as measured by APACHE II and Pitt bacteremia scores was identical.
Second,we were unable to de?ne optimal duration of combina-tion therapy because antibiotic therapy was changed in35%of patients by Day5.Patients receiving monotherapy who were doing poorly often received additional antibiotics,whereas patients re-ceiving combination therapy often had antibiotics tapered because of knowledge of in vitro susceptibility or improvement in clinical status.
Third,we were unable to clearly delineate the basis for the superiority of the combination regimen,and we were unable to precisely determine which speci?c components of combination therapy would be most effective.Earlier retrospective analyses (6,8)of two smaller study populations suggested that the addi-tion of a macrolide to a?-lactam was the best combination regimen.In our study not only were regimens that included macro-lides as one of the combination agents associated with better outcomes,but nonmacrolide combination regimens were also suc-cessful in reducing mortality among the severely ill patients.Thus, the unique role of macrolides possessing antiin?ammatory activity and/or coverage against atypical copathogens postulated by other investigators could not be supported.
In the report of a retrospective study of pneumococcal bacter-emia,Austrian and Gold demonstrated that some patients,de-spite appropriate antibiotic therapy and critical supportive care (as was available more than four decades ago),“cannot be pre-vented from dying”(16).It is dif?cult to make direct comparisons between this retrospective study(14)and our prospective obser-vational study.Nevertheless,the dramatic reduction in early mor-tality among severely ill patients in our current investigation has led us to speculate that combination antibiotic therapy might sal-vage some critically ill patients who might be otherwise“destined to die”(6).
We emphasize that the potential bene?ts of combination anti-biotic therapy in our study and in the Waterer and coworkers study(7)were limited to more severely ill patients.For noncriti-cally ill patients,there was no difference in the14-day mortality for patients treated with monotherapy versus combination ther-apy(Figure1A).Because the overall mortality of patients with mild illness due to bacteremic pneumococcal illness is so low, minimal bene?t will be gained by adding a second antibiotic. As mentioned,the optimal duration of combination therapy is unde?ned,but because mortality is highest within the?rst3days (Figure1)(10),it seems both intuitive and reasonable that3–5 days might be suf?cient.If our conclusions are con?rmed by other prospective studies,we recommend that clinicians target combina-tion antibiotic treatment only for those patients who are critically ill,and limit the duration of the combination to3–5days.Such an approach may be bene?cial yet minimize antibiotic overuse. Conflict of Interest Statement:L.M.B.received$10,660from Bristol-Myers Squibb for2001and$5,000for2002for speaking at conferences and received$6,500 in2001and$7,000in2002from Schering for speaking at conferences;V.L.Y. declares that Roche is providing funding for a study of bacterial meningitis that is distinct from this study and that the submitted study was unfunded;K.P.K.has served as a consultant,member of an advisory board,and/or lectured in symposia sponsored by Abbott Laboratories,Bayer Corporation,Bristol-Myers Squibb Com-pany,GlaxoSmithKline Pharmaceuticals,Aventis,and Wyeth Ayerst Laboratories and his research unit currently receives research funding from Roche,Bayer, Aventis,and Oscient Pharmaceuticals and he has served as an expert witness for GSK and GENESOFT;C.F.has acted on the advisory board of pharmaceutical companies marketing antibiotics(Abbott,Aventis,Bristol-Meyers Squibb,Pfizer/ Pharmacia,and MSD),has been reimbursed for lectures sponsored by pharmaceu-tical companies(Pfizer,Abbott,Bristol-Meyers Squibb,GlaxoSmithKline,Bayer, and MSD),and has attended conferences sponsored by pharmaceutical compa-nies(Bristol-Meyers Squibb,Aventis,Pfizer,and GlaxoSmithKline);A.O.received $2,000in2001and$2,000in2002for serving on an advisory board for Bayer and$1,000in2001for speaking at conferences sponsored by Bayer;J.R.does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript;A.J.M.does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript;C.M.L. has participated as a speaker in scientific meetings or courses organized and financed by various pharmaceutical companies(Merck,Sharpe&Dohne;Bayer; Pfizer;Bristol Myers;and Squibb);D.R.S.has received unrestricted and restricted research support from Merck,Astra Zeneca,Pfizer,and Bayer in2003and2004 and from Wyeth Ayerst in2004and has lectured on behalf of Bayer,Merck, Roche,and Pfizer in the past year;W.C.K.does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript;M.B.F.C. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript;D.S.H.does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript;A.A.has been a consultant on an advisory board for Aventis in2003/2004receiving C?1,500 each year and in2004gave a lecture on antibiotics in an Aventis-sponsored meeting during the meeting of the National Society of Infectious Disease;C.C.C.C.does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript.
Acknowledgment:The authors thank Marilyn Wagener for statistical analysis and major assistance in presentation of the results.
References
1.Macfarlane J.Severe pneumonia and a second https://www.sodocs.net/doc/149556191.html,ncet2002;359:
1170–1172.
2.Macfarlane JT,Boswell T,Douglas G,Finch R,Holmes W,Honeybourne
D.British Thoracic Society guidelines for the management of commu-
nity acquired pneumonia in adults.Thorax2001;56:1–64.
3.Niederman MS,Mandell LA,Anzueto A,Bass JB,Broughton WA,
Campbell GD,Dean N,File T,Fine MJ,Gross PA,et al.,American Thoracic Society.Guidelines for the management of adults with community-acquired pneumonia:diagnosis,assessment of severity,an-timicrobial therapy,and prevention.Am J Respir Crit Care Med2001;
163:1730–1754.
4.Barlett JG,Dowell SF,Mandell LA,File TM Jr,Musher DM,Fine
MJ.Practice guidelines for the management of community-acquired pneumonia in adults.Clin Infect Dis2000;31:347–382.
5.Mandell LA,Marrie TJ,Grossman RF,Chow AW,Hyland RH,Canadian
Community-acquired Pneumonia Working Group.Canadian guide-lines for the initial management of community-acquired pneumonia: an evidence-based update by the Canadian Infectious Diseases Society and the Canadian Thoracic Society.Clin Infect Dis2000;31:383–421.
6.Mufson MA,Stanek RJ.Bacteremic pneumococcal pneumonia in one
444AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL1702004
American city:a20-year longitudinal study,1978–1997.Am J Med1999;
107:34S–43S.
7.Waterer GW,Somes GW,Wunderick RG.Monotherapy may be subopti-
mal for severe bacteremic pneumococcal pneumonia.Arch Intern Med 2001;161:1837–1842.
8.Martinez JA,Horcajada JP,Almela M,Marco F,Soriano A,Garcia E,
Marco MA,Torres A,Mensa J.Addition of a macrolide to a B-lactam-based empirical antibiotic regimen is associated with lower in-hospital mortality for patients with bacteremic pneumococcal pneumonia.Clin Infect Dis2003;36:389–395.
9.File TM Jr,Mandell LA.What is optimal antimicrobial therapy for bacter-
emic pneumococcal pneumonia?Clin Infect Dis2003;36:396–398.
10.Yu VL,Chiou CC,Feldman C,Ortqvist A,Rello J,Morris AJ,Baddour
LM,Luna CM,Snydman DR,Ip M,Ko WC,Chedid MB,Andremont A,Klugman KP,International Pneumococcal Study Group.An inter-national prospective study of pneumococcal bacteremia:correlation with in vitro resistance,antibiotics administered,and clinical outcome.
Clin Infect Dis2003;37:230–237.
11.Paterson DL,Ko WC,Von Gottberg A,Trenholme G,Klugman KP,
Bonomo R,Rice LB,Wagener MW,McCormack JG,Yu VL.Interna-tional prospective study of Klebsiella pneumoniae bacteremia:implica-tions of extended-spectrum-?-lactamase production in nosocomial infections.Ann Intern Med2004;140:2632.
https://www.sodocs.net/doc/149556191.html,ler LH.Survival analysis.Chapter5.New York:John Wiley&Sons;
1981.
13.NCCLS.Performance standards for antimicrobial susceptibility testing:
twelfth informational supplement.Wayne,PA:National Committee for Clinical Laboratory Standards;2002.NCCLS Document M100S12.
14.Kalin M,Ortqvist A,Almela M,Aufwerber E,Dwyer R,Henriques B,
Jorup C,Julander I,Marrie TJ,Mufson MA,Riquelme R,Thalme A,Torres A,Woodhead MA.Prospective study of prognostic factors in community-acquired bacteremia pneumococcal disease in5coun-tries.J Infect Dis2000;182:840–847.
15.Brown RB,Iannini P,Gross P,Kunkel M.Impact of initial antibiotic
choice on clinical outcomes in community-acquired pneumonia:analy-sis of a hospital claims-made database.Chest2003;123:1503–1511. 16.Austrian R,Gold J.Pneumococcal bacteremia with especial reference
to bacteremic pneumococcal pneumonia.Ann Intern Med1964;60:759.
(整理)低辐射镀膜玻璃标准.
镀膜玻璃标准第2部分：低辐射镀膜玻璃 GB/T 18915.2一2002 前言 GB/T 18915《镀膜玻璃》分为两部分： 第1部分；阳光控制镀膜玻璃 第2部分：低辐射镀膜玻璃 本部分为GB/T 18915《镀膜玻璃》的第2部分。 本部分由原国家建筑材料工业局提出。 本部分由全国建筑用玻璃标准化技术委员会归口。 本部分负责起草单位：中国建筑材料科学研究院玻璃科学与特种玻璃纤维研究所。 本部分参加起草单位：中国南玻科技控股（集团）股份有限公司、广东金刚玻璃科技股份有限公司。 本部分起草人：韩松、杨建军、莫娇、吴洁、周安心、朱梅、庄大建、龙霖星。 1 范围 GB/T 18915的本部分规定了低辐射镀膜玻璃的分类、要求、试验方法、检验规则及包装、标志、贮存和运输。 本部分适用于建筑用低辐射镀膜玻璃，其他方面使用的低辐射镀膜玻璃也可参照本部分。 2 规范性引用文件
下列文件中的条款通过本部分的引用而成为本部分的条款。凡是注日期的引用文件，其随后所有的修改单（不包括勘误的内容）或修订版均不适用于本部分，然而，鼓励根据本部分达成协议的各方研究是否可使用这些文件的最新版本。凡是不注日期的引用文件，其最新版本适用于本部分。 GB/T 2680 建筑玻璃可见光透射比、太阳光直接透射比、太阳能总透射比、紫外线透射比及有关窗玻璃参数的测定（GB/T 2680-1994,neq ISO 9050:1990) GB/T 2828-1987 逐批检查计数抽样程序及抽样表（适用于连续批的检查） GB/T 6382. 1 平板玻璃集装器具架式集装器具及其试验方法 GB/T 6382. 2 平板玻璃集装器具箱式集装器具及其试验方法 GB/T 8170 数值修约规则 GB 11614 浮法玻璃 GB 17841-1999 幕墙用钢化玻璃与半钢化玻璃 GB/T 18915. 1 镀膜玻璃第1部分阳光控制镀膜玻璃 1C/T 513 平板玻璃木箱包装 3 术语和定义 下列术语和定义适用于GB/T 18915的本部分。 辐射率emissivity
中空玻璃的k值
中空玻璃的k值 点击数：606加拿大联合太平洋有限公司王铁华 引言 2000年2月18日国家建设部俞正声部长签署了 《关于民用建筑节能管理规定》中华人民共和国建 设部令。该规定对包括建筑门窗的节能标准，政策 及实施的时间作了政策性的规定。 在实践中，如何具体测试影响中空玻璃节能性能的 指标即热传导值K值(或U值)，人们的认识是比较 混乱的。有的认为中空玻璃的K值(或U值)应该是中央玻璃的K值，有的认为中空玻璃K值应该是中空玻璃上几处不同点的平均值。结果，对同一中空玻璃，采用不同方法测试所得到的K值却是不同的。 可见，实践迫切需要理论给予指导。我们认为，测试中空玻璃K值的方法必须同时满足准确和科学两个基本条件。准确，要求K值必须而且能够反应出某一中空玻璃的确切的热传导值。比如，使用温暖边缘隔条制成的中空玻璃与传统的铝隔条中空玻璃的热传导值是不同的。科学，要求测试中空玻璃的方法必须有实践和理论方面的依据，反应实际情况。实际情况是，玻璃边缘的热传导系数与玻璃中央的热传导系数是不同的。 本文拟对北美中空玻璃协会对中空玻璃的K值(即热传导值)的规定及其测试方法作以下介绍，抛砖引玉。 一、基本概念 首先应明确几个彼此相关但又不同概念，它们是中空玻璃的综合K值(或U值)，中空玻璃中央的K值，中空玻璃边缘的K值，及中空玻璃间隔条的K值。中空玻璃综合K值是中空玻璃中央、边缘和间隔条K 值的加权平均数。 1.中空玻璃边缘K值 中空玻璃边缘定义为距离间隔条内侧63.5mm(21/2英寸)间隔的条形面积。中空玻璃边缘K值是在此面积上所测试得到的。 2.中空玻璃间隔条K值 中空玻璃间隔条K值是间隔条本身的K值。不同的隔条的K值不同。铝隔条K值>不锈钢隔条>舒适胶条>超级间条。 3.中空玻璃的面积 中空玻璃面积是可视面积和镶嵌在窗框内的面积之合。 4.中空玻璃中央的K值 中空玻璃中央定义为整个中空玻璃的面积减去中空玻璃边缘的条形面积。（如图1）
镀膜玻璃检验规则
镀膜玻璃检验规则 RDBL/WJ-7.5.1-15 一、做好生产前的准备工作 1、根据派产单要求，落实基片。重点注意五件事： ⑴如合同为配片，必须保证本次和上次基片为同一生产厂家。如采用不同厂家的基 片应先做颜色对比测试，确定透光率、L*、a*、b*等光学指标的偏差均小于1.0，方可 通知切裁。 ⑵镀膜使用的基片应为下线不超4周的浮法玻璃,如有超期,需在生产前进行清洗验 收。对明显有纸纹和霉点的玻璃禁止使用，如有轻微发霉，则请示主管领导同意后， 在磨料罐中加适量抛光粉。 ⑶钢化或切裁过来的半成品玻璃，提前签收，在玻璃签收本上按架做好签收记录， 并根据合同捡单打印尺寸标签、粘贴标签，标签必须贴在锡面。 ⑷如有异形玻璃，根椐派产单要求，按图纸复核尺寸及该镀那个面，贴好尺寸标签。 ⑸对于来料加工，要对清洗后的玻璃认真检验，检验内容包括纸纹、霉点、划伤、 爆边、裂纹、缺角、弯曲、表面污染等，填写《顾客提供产品报告单》，如客户在现 场，则请代表当场签字。如客户不在我公司，则转由业务科发传真要求对方确认。 2、根据派产单加工要求，准备工艺资料。 ⑴核实派产单指定的膜系，把相应的颜色标准提前输入色谱仪，并记录档位。 ⑵如为配片合同，则调用该客户上一次的生产记录。如不配片，写有“颜色同本厂”， 则调用最近期生产的与本厂标准最接近的此种产品的生产记录。统计上次生产的偏差 方向和偏差范围，并做好记录以备生产时使用。 ⑶如为来样生产，则进行采样测试，获取来样的R□、T、R g 、R f ；L*g、a*、b*g；l*f、 a*f、b*f，并做好记录，以便以此为标准进行调试和生产。如按样验收，封样应封荣达试样。 二、准备工作做好后开机调试 1、先把等待室南面的空气净化打开。 2、配合工艺员，调试小片。 （1）按照《检测仪器操作指导书》要求标定好色谱仪并调到事先录入标准的档位。 （2）逐锅测试小片中间位置颜色偏差值，并及时与工艺员沟通，当单项色
镀膜玻璃内控标准QMS06
镀膜玻璃内控标准 1.适用范围 本标准适用于本公司镀膜玻璃检验、判定 2. 引用文件 GB/T18915.1/2-2002镀膜玻璃 GB11614浮法玻璃 3. 分类及应用 3.1按镀膜玻璃对太阳光的控制区域的不同分类：热反射镀膜玻璃、低辐射镀膜玻璃 3.2按热加工性能可分为：非钢化镀膜玻璃、钢化镀膜玻璃、可钢化镀膜玻璃 4.术语及定义 4.1热反射镀膜玻璃：又称阳光控制膜镀膜玻璃，对波长范围350nm~1800nm的太阳光具有一定控制作用，一般是金属或非金属氧化物或氮化物膜层构成 4.2低辐射镀膜玻璃：又称Low-E玻璃，是一种对波长范围4.5μm~25μm的远红外线有较高反射比的镀膜玻璃 4.3脱膜：从镀膜玻璃透射方向看,相对膜层整体可视透明部分或全部没有附着膜层的缺陷4.4斑点：从镀膜玻璃的透射方向看,相对膜层整体色泽较暗的点状缺陷 4.5斑纹：从镀膜玻璃的反射方向看，膜层表面色泽发生变化的云状.放射状或条纹状的缺陷4.6色道：从镀膜玻璃的反射方向看，膜层表面亮度或反射色异于整体的条状区域，可见程度取决于它们和周围膜层的亮度及颜色差 4.7色差：从镀膜玻璃的反射方向看，膜层表面亮度或反射色异于标准板，可见程度取决于标板亮度及颜色差 4.8划伤：镀膜玻璃表面各种线状的划痕.可见程度取决于它们的长度.宽度.位置和分布 4.9氧化：Low-E玻璃受环境影响，致使膜层结构破坏、产品性能失效，具体表现为雪花状、或点状的氧化点 5、要求： 5.1外观:
5.2光学要求：满足下表
5.3均匀性：其均匀性反射色色差不得大于2.0CIELAB，采用CIELAB均匀色空间的色差ΔE 来表示，单位CIELAB。 5.4批次色差：反射色色差不得大于2.0CIELAB 5.5理化性能：热反射镀膜玻璃△T≤4.0%;Low-E玻璃无此要求 5.6包装要求：满足《钢化镀膜玻璃包装作业指导书》、《镀膜大板包装作业指导书》要求 6、检验方法 6.1 外观中脱膜.斑点.划伤的测定：使用装有数只间距300mm的40瓦平行日光灯管的黑色无光泽屏幕。阳光控制镀膜玻璃垂直放置，与日光灯管平行且相距600mm，观察者距玻璃600mm，视线垂直玻璃进行观察，缺陷尺寸用精度0.1mm的读数显微镜测定。 6.2斑纹.色道的测定：阳光控制镀膜玻璃放置在倾斜60°~75°的黑色无光泽屏幕（黑车），玻璃面面向观察者，观察者距离玻璃1.5米外，自然光室外目测 6.3光学要求：以镀膜线在线光度计测试数据为依据，参考Color I5透过率测试数据进行判定6.4均匀性：以镀膜线在线光度计测试数据为依据，调试均匀性整体平滑、无突变测试点（连续3点L*、a*、b*均小于0.8）为合格。产品均匀性以调试均匀性为生产依据，产品须考虑边缘效应的安装对接，即均匀性方向的产品边部L*≤1.0、a*、b*均小于0.8 6.5色差：以镀膜线在线光度计测试数据为依据，结合Color I5透过率、玻面反射、膜面反射测试数据和DateColor手提测色仪玻面反射色进行综合判定，在线光度计批次色差控制满足：反射R≤15%色差：L*≤1.0、a*、b*≤0.5; 15%＜反射R≤22%色差：L*≤1.5、a*、b*≤0.6;反射R＞22%色差：L*≤1.5、a*、b*≤0.8;工程批次色差控制还应注意第一批的颜色偏向，后面各批因控制在第一批颜色与标准色之间;工程第一批应与标准板室外目测色差，无明显差别为合格。标准板可以为我司的常规产品样板或客户提供给我司的工程色板，客户提供工程色板的第一次生产要留样板 6.6所有的外观缺陷、色差、色道在条件允许的情况下，以实际室外目测效果为准 6.7理化性能：包括研磨试验、酸碱腐蚀试验，具体操作见GB/T18915.1-200和各仪器设备操作作业指导书 6.8包装：参考《钢化镀膜玻璃包装作业指导书》、《镀膜大板包装作业指导书》 7、运输、储存要求： 运输时要有防雨措施；储存的房间干燥、通风、非太阳直射
中空玻璃节能特性的影响因素分析(精)
中空玻璃节能特性的影响因素分析 一、建筑节能对玻璃性能的要求随着社会经济发达程度的提高，建筑能耗在社会总能耗中的所占比例越来越大，目前西方发达国家约为30%~45%，尽管我国经济发展水平和生活水平都还不高，但这一比例已达到20%~25%，正逐步上升到30%。在一些大城市，夏季空调已成为电力高峰负荷的主要组成部分。不论西方发达国家，还是我国，建筑能耗状况都是牵动社会经济发展全局的大问题。按照1986年制定的我国建筑节能分三步走的计划，当前政府各级节能管理部门正在积极启动实现第三步节能65%目标的标准编制工作。而在影响建筑能耗的门窗、墙体、屋面、地面四大围护部件中，门窗的绝热性能最差，是影响室内热环境质量和建筑节能的主要因素之一。就我国目前典型的围护部件而言，门窗的能耗约占建筑围护部件总能耗的40%~50%。据统计，在采暖或空调的条件下，冬季单玻窗所损失的热量约占供热负荷的 30%~50%，夏季因太阳辐射热透过单玻窗射入室内而消耗的冷量约占空调负荷的20%~30%。因此，增强门窗的保温隔热性能，减少门窗的能耗，是改善室内热环境质量和提高建筑节能水平的重要环节。中空玻璃具有突出的保温隔热性能，是提高门窗节能水平的重要材料，近些年已经在建筑上得到了极其广泛的使用。但随着节能标准的不断提高，普通的中空玻璃已不能完全满足节能设计的技术要求。例如在夏热冬冷地区的节能设计标准中，对大窗墙比的外窗传热系数限制指标到了2.5 W/m2K，夏热冬暖地区这一指标在部分条件下到了2.0 W/m2K。所以我们应该一方面大力推广Low-E中空玻璃这种具有优良节能特性的新产品，另一方面要深入分析和掌握中空玻璃节能性能的各个影响因素，从玻璃原片、间隔组成和使用环境等方面保证中空玻璃能够发挥它最佳的节能性能。二、中空玻璃节能特性的基本指标在建筑用中空玻璃诸多的性能指标中，能够用来判别其节能特性的主要有传热系数K和太阳得热系数SHGC。中空玻璃的传热系数K是指在稳定传热条件下，玻璃两侧空气温度差为1℃时，单位时间内通过1平方米中空玻璃的传热量，以W/m2K 表示。K值越低，说明中空玻璃的保温隔热性能越好，在使用时的节能效果越显著。太阳得热系数SHGC是指在太阳辐射相同的条件下，太阳辐射能量透过窗玻璃进入室内的量与通过相同尺寸但无玻璃的开口进入室内的太阳热量的比率。玻璃的SHGC值增大时，意味着可以有更多的太阳直射热量进入室内，减小时则将更多的太阳直射热量阻挡在室外。SHGC值对节能效果的影响是与建筑物所处的不同气候条件相联系的，在炎热气候条件下，应该减少太阳辐射热量对室内温度的影响，此时需要玻璃具有相对低的SHGC值；在寒冷气候条件下，应充分利用太阳辐射热量来提高室内的温度，此时需要高SHGC值的玻璃。在K值与SHGC值之间，前者主要衡量的是由于温度差而产生的传热过程，后者主要衡量的是由太阳辐射产生的热量传递，实际生活环境中两种影响同时存在，所以在各建筑节能设计标准中，是通过限定K和SHGC的组合条件来使窗户达到规定的节能效果。目前，中空玻璃的K值是通过实验室实际测量得出的，SHGC值是对光谱数据计算得出的。因为K值的实际测量受成本限制难以收集各种类型的大量数据，所以本文的分析过程将采用美国劳伦斯伯克利实验室开发的Window5.2软件进行模拟计算。该软件能够计算出各种类型玻璃的K值和SHGC值等相关参数，其计算结果可以近似代替实际测量值。为了保证计算结果的一致性，除特殊说明以外，本文在计算分析中采用NFRC系列标准的环境条
ASTM JIS EN与中国国家标准对比详细情况(钢化镀膜中空(xiugai))解析
培训资料 一、标准知识简介 1.我国标准的体制 1.1我国标准分级（四级）及编号： 分级：国家标准---行业标准---地方标准----企业标准 编号：国家标准的编号由国家标准的代号（GB）、发布的顺序号、发布的年号三部分组成；如GB/T18915.1-2002 行业标准的编号由行业标准的代号（如JB）、发布的顺序号、发布的年号三部分组成。 地方标准的编号由地方标准的代号（DB）加上省、自治区、直辖市行政区代码前两位数、再加斜线、加发布发布的顺序号、发布的年号 企业标准的编号没有规定 1.2我国标准的性质： 《中华人民共和国标准化法》规定，国家标准和行业标准分为强制性和推荐性两种。 1.2.1强制性标准： 强制性标准分为全文强制（标准的全部技术内容需强制）和条文强制（标准中部分技术内容需强制）两种 保障人体健康、人身、财产安全的标准和法律、行政法规规定强制执行的标准是强制性标准。《中华人民共和国标准化法》同时还规定，省、自治区、直辖市标准化行政主管部门制定的工业产品的安全、卫生要求的地方标准，在本行政区域内是强制性标准。 《中华人民共和国标准化法》规定“强制性标准必须执行，不符合强制性标准的产品，禁止生产、销售和进口”，违反强制性标准就是违法，就要受到法律制裁。其法律地位是由国家有关法律赋予的。 第 1 页共36 页
1.2.2 推荐性标准： 强制性标准以外的标准是推荐性标准，是指生产、交换、使用等方面，通过经济手段调节而自愿采用的一类标准，又称自愿性标准。这类标准任何单位都有权决定是否采用，违反这类标准，不承担经济和法律方面的责任。但是，一经接受采用，或各方面商定同意纳入商品、经济合同之中，就成为各方共同遵守的技术依据，具有法律上的约束力。 2.采用国际标准和国外先进标准 （1）国际标准：是指国际标准化组织（ISO）、国际电工委员会（IEC）和国际电信联盟（ITU）制定的标准，以及由国际标准化组织确认并公布的其他国际组织（如CIE）制定的标准。国际标准在世界范围内使用。 （2）外先进标准：是指未经国际标准化组织（ISO）确认并公布的其他国际组织的标准、发达国家的国家标准、区域性组织的标准、国际上有权威的团体标准和企业（公司）标准中的先进标准。 有影响的区域性标准如：欧洲标准化委员会（CEN）； 世界上主要经济发达国家的国家标准如：美国国家标准（ANSI）、美国军用标准（MIL）、德国国家标准（DIN）、英国国家标准（BS）、日本工业标准（JIS）等。 国际上有权威的团体标准如：美国材料与试验协会（ASTM）、美国机械工程师协会（ASME） （3）采用国际标准和国外先进标准：是指将其内容，经过分析研究和试验验证，等同和修改转化为我国国家标准、行业标准、地方标准和企业标准。 （4）采用国际标准和国外先进标准的一般方法：认可法、封面法、完全重印法、翻译法、重新起草法和引用法。 （5）采用国际标准和国外先进标准的程度和表示方法 采用程度分为两种： 等同采用：在技术内容和文本结构上相同，或在技术内容上相同，只存在少量编辑性修改。符号≡，程度代号IDT（identical）。 修改采用：在技术内容上存在差异，在文本结构上应对应。符号＝，程度代号MOD（modified）。 第 2 页共36 页
中空玻璃可行性分析报告
中空玻璃可行性分析报告 目录 一、建筑节能与中空玻璃市场情况 二、中空玻璃加工企业的明显特点 三、中空玻璃产品利润分析
一、建筑节能与中空玻璃市场情况 中空玻璃的概念出现在国内市场已经有很长时间了，Low-E玻璃的出现也已经有10年左右的时间。尽管这些产品具有很好的节能、保温和隔音等显著改善居住条件的优良性能，但是这些好产品更多地是使用在公共建筑和高档建筑上，绝大部分民用建筑至今依然较少看到中空玻璃，更谈不上Low-E玻璃，许多消费者至今还以为中空玻璃就是两片玻璃的简单组合。造成中空玻璃和Low-E 玻璃贵族化问题的主要原因有两方面：一是国内房地产市场发展速度过快，许多地产商根本无心关注门窗和玻璃性能等细节；二是门窗企业和加工玻璃企业更多地关注高档楼盘而忽视了民用建筑市场的推广。 可喜的是，从贵族化转向平民化的过程正在开始。伴随着国内房地产业逐步进入常规发展轨道，开发商和购房者开始共同关注楼盘品质和部品细节，加之经过10余年的市场推广，中空玻璃和Low-E玻璃的优良性能已被市场所认识和接受。中空玻璃进入寻常百姓家，不仅是节能的需要，更是提高人们生活品质的需要。 1建筑节能形势与政策 1.1减少门窗能耗，提高建筑节能水平 随着社会经济发达程度的提高，建筑能耗在社会总能耗中的所占比例越来越大，目前西方发达国家为30％～45％，尽管我国经济发展水平和生活水平都还不高，但这一比例已达到20％～25％，正逐步上升到30％。在一些大城市，夏季空调已成为电力高峰负荷的主要组成部分。不论西方发达国家还是我国，建筑能耗状况是牵动社会经济发展全局的大问题。按照1986年制定的我国建筑节能分三步走的计划，当前政府各级节能管理部门为了启动第三步节能65％的目标，正在积极地进行标准编制工作。而在影响建筑能耗的门窗、墙体、屋面、地面四大围护部件中，门窗的绝热性能最差，是影响室内热环境质量和建筑节能的主要因素之一。就我国目前典型的围护部件而言，门窗的能耗占建筑围护部件总能耗的40％～50％，其能耗是墙体的4倍、屋顶的5倍、地面的20多倍。我国既有建筑面积约400亿m2，95％以上是高能耗建筑，而透过门窗的能耗则占到了整个建筑的一半，堪称耗能大户。能耗比同等气候条件下的发达国家高2倍。如果按照我国现有发展的趋势，2020年以后，建筑耗能将超过我国终端能耗的1/3，
建筑玻璃系列的国家标准
一、建筑玻璃的标准体系 1、建筑玻璃 平板玻璃是指板状的硅酸盐玻璃。它主要有用垂直引上法和平拉法生产的普通平板玻璃；用浮法工艺生产的浮法平板玻璃；采用浮法工艺生产的，成份中三氧化二铁含量不大于0.015%，具有高可见光透射率比的平板玻璃；用压延法生产的表面带有花纹图案、透光但不透明的压花平板玻璃；用压延法生产的内部夹有金属丝或网的夹丝平板玻璃；并在上述玻璃成份中加入着色剂使玻璃显现一定颜色的着色平板玻璃。 曲面玻璃是在平板玻璃经二次热加工而形成的曲面玻璃也可称为热弯玻璃。 为提高玻璃的强度、保证玻璃的安全性和增加玻璃的使用功能，经二次加工制成防火玻璃；钢化玻璃（钢化玻璃又分为物理钢化玻璃和化学钢化玻璃；物理钢化玻璃又分为半钢化玻璃、钢化玻璃和均值钢化玻璃）；镀膜玻璃（可分为离线镀膜玻璃和再线镀膜玻璃）；釉面玻璃等。 为了满足建筑的需要直接采用上述玻璃的单片和采用上述玻璃经合成而形成的中空玻璃和真空玻璃。 为了满足建筑的特殊需要而制成的镶嵌玻璃、建筑用U型玻璃、光栅玻璃、防弹玻璃、空心玻璃砖贴膜玻璃、和建筑玻璃制品等。 二、建筑玻璃标准对的技术和质量要求 1、GB 11614-2009《平板玻璃》对平板玻璃质量要求（其中对尺寸偏差、对角线差、厚度偏差、厚薄差、外观质量和弯曲度的要求为强制性的要求，光学特性和特殊厚度或其他要求为推荐性的要求）如下表。
2、JC/T 511-2002《压花玻璃》对用压延法生产的表面带有花纹图案、透光但不透明的平板玻璃（花纹玻璃或滚花玻璃）的技术要求如下表，压花玻璃有无色、有色、彩色数种。
4、GB 15763.2-2005《建筑用安全玻璃第2部份：钢化玻璃》对经热处理工艺之后的玻璃。其特点是在玻璃表面形成压应力层，机械强度和耐热冲击强度得到提高，并具有特殊的碎片状态的钢化玻璃；GB 15763.4-2009《建筑用安全玻璃第4部份：均质钢化玻璃》对经过特定工艺条件处理过的钠钙硅钢化玻璃（简称HST）的均质钢化玻璃（热浸钢化玻璃）；JC/T977-2005《化学钢化玻璃》对通过离子交换，玻璃表层碱金属离子被熔盐中的其它碱金属离子置换，使机械强度提高的化学钢化玻璃的技术要求如下表。
中空玻璃在节能方面的应用意义论文
中空玻璃在节能方面的应用意义 摘要：我们国家把节能降耗工作看作是贯彻落实科学发展观、构建社会主义和谐社会的重要内容，是建设资源节约型、环境友好型社会的必然选择，对于调整经济结构、转变增长方式、提高人民生活质量、维护中华民族长远利益，具有极其重要而深远的意义。文章介绍的是中空玻璃在建筑节能方面的应用 关键词：建筑节能；建筑幕墙；中空玻璃 abstract: our country is seen as the energy conservation and consumption reduction to implement the scientific development concept and the construction of socialist harmonious society’s important content, is building a resource-conserving, environment-friendly society’s inevitably choice, for the adjustment of economic structure, transforming growth mode, improving people’s life quality, and maintaining long-term interests of the chinese nation, has the extremely important and profound significance. this paper is hollow glass in the application of building energy efficiency keywords: building energy efficiency; the construction curtain wall; hollow glass 中图分类号：tu201.5 文献标识码：a 文章编号：
镀膜玻璃行业分析报告
镀膜玻璃 行业分析报告行业调研及投资分析
镀膜玻璃行业分析报告目录 第一章宏观环境分析 第二章行业发展概况 第三章区域内行业发展形势分析 第四章重点企业调研分析 第五章重点投资项目分析 第六章总结及展望
第一章宏观环境分析 一、产业发展分析 玻璃是非晶无机非金属材料，一般是用多种无机矿物（如石英砂、硼砂、硼酸、重晶石、碳酸钡、石灰石、长石、纯碱等）为主要原料，另外加入少量辅助原料制成的。它的主要成分为二氧化硅和其他氧化物。普通玻璃的化学组成是Na2SiO3、CaSiO3、SiO2或 Na2O?CaO?6SiO2等，主要成分是硅酸盐复盐，是一种无规则结构的 非晶态固体。 （一）产业政策分析 1、《中华人民共和国节约能源法》 国家鼓励在新建建筑和既有建筑节能改造中使用新型墙体材料等 节能建筑材料和节能设备，安装和使用太阳能等可再生能源利用系统。 2、《国务院关于促进光伏产业健康发展的若干意见》 远近结合，标本兼治。在扩大光伏发电应用的同时，控制光伏制 造总产能，加快淘汰落后产能，着力推进产业结构调整和技术进步。 统筹兼顾，综合施策。统筹考虑国内外市场需求、产业供需平衡、上下游协调等因素，采取综合措施解决产业发展面临的突出问题。
市场为主，重点扶持。发挥市场机制在推动光伏产业结构调整、 优胜劣汰、优化布局以及开发利用方面的基础性作用。对不同光伏企 业实行区别对待，重点支持技术水平高、市场竞争力强的骨干优势企 业发展，淘汰劣质企业。 协调配合，形成合力。加强政策的协调配合和行业自律，支持地 方创新发展方式，调动地方、企业和消费者的积极性，共同推动光伏 产业发展。 3、《能源发展战略行动计划（2014-2020年）》 提高天然气消费比重，大幅增加风电、太阳能、地热能等可再生 能源和核电消费比重。鼓励有条件的地区发展热电冷联供，发展风能、太阳能、生物质能、地热能供暖。加快发展太阳能发电。有序推进光 伏基地建设，同步做好就地消纳利用和集中送出通道建设。加快建设 分布式光伏发电应用示范区，稳步实施太阳能热发电示范工程。加强 太阳能发电并网服务。鼓励大型公共建筑及公用设施、工业园区等建 设屋顶分布式光伏发电。到2020年，光伏装机达到1亿千瓦左右，光 伏发电与电网销售电价相当。 4、《促进绿色建材生产和应用行动方案》
中空玻璃间距多少最节能
中空玻璃间距多少最节能 中空玻璃很节能，但是你知道，玻璃间距多少的时候，节能效果最好吗？ 常用的中空玻璃间隔层厚度有6mm、9mm、12mm、15mm等规格。 气体间隔层的厚薄与热阻的大小有着直接的联系。 在玻璃材质、密封构造相同的情况下，气体间隔层越大，热阻越大。 但气体层的厚度达到一定程度后，热阻的增长率就很小了。因为当气体层厚度增到一定程度后，气体在玻璃之间温差的作用下，就会产生一定的对流，从而减低了气体层增厚的作用。 如图所示，气体层从1mm增加到9mm时，白玻中空充填空气时的K值下降37%，Low-E中空玻璃充填空气时的K值下降53%，充填氩气时下降59%。从9mm增加到13mm时，下降速度都开始变缓。13mm以后，K值反而有轻微的回升。所以对于6mm厚度玻璃的中空组合，超过13mm的气体间隔层厚度不会产生明显的节能效果。
产生以上现象的原因是什么？ 当间隔层厚度小于10mm时，间隔层内热量以传导传递为主。 当间隔层厚度超过13mm时，对流传热开始逐步增大，抵消了空气层因增厚带来的热阻。中空玻璃的隔热系数，整体反而变化不大了。 综合考虑以上因素，合理的中空玻璃间隔层厚度，应该是12mm 左右。
从上面的图中，我们同时还能看到： 气体间隔层厚度增加时，Low-E中空玻璃的K值下降速度比普通中空玻璃要块。 玻璃间隔层填充氩气，能明显提高节能效果。 这里就要说下了，中空玻璃间隔层内部充填的气体，除空气外，还有氩气、氪气等惰性气体。空气的导热系数为0.024W/（m·K），氩气的导热系数为0.016W/（m·K）。由于气体的导热系数很低，因此极大地提高了中空玻璃的热阻性能。 以6mm+12mm+6mm的白玻中空组合为例：
镀膜玻璃国家标准英文版
5.3 Appearance Quality The appearance quality of the sunlight-controlled coated glass sheet should meet the technical requirements of vehicle grade in GB 11614. The tempered and semi-tempered sunlight-controlled coated glass sheet used as curtain wall should have fine edge processing. The appearance quality of the sunlight-controlled coated glass sheet should meet the requirements of Chart 1. Chart 1 The Appearance Quality of the Sunlight-Controlled Coated glass Sheet Defect Description Superior Product Conforming Product Pinhole Diameter<0.8mm Intensive not allowed 0.8mm≦Diameter<1.2mm Middle:3.0*S,pcs,Distanc e between each pinhole bigger than 300mm. 75mm edge;Intensive not allowed Intensive not allowed 1.2≦Diameter<1.6mm Middle:not allowed 75mm edge:3.0*S,pcs Middle:3.0*S,pcs 75mm edge:8.0*S,pcs 1.6mm≦Diameter≦2.5mm not allowed Middle:2.0*S,pcs 75mm edge:5.0*S,pcs Diameter>2.5mm not allowed not allowed Spot 1.0mm≦Diameter≦2.5mm Middle:not allowed 75mm edge:2.0*S,pcs Middle:5.0*S,pcs 75mm edge:6.0*S,pcs 2.5
Lowe玻璃和镀膜玻璃
L o w-e的反射颜色为紫色。LOW-E玻璃 Low-E玻璃又称低辐射玻璃，在玻璃表面镀上多层金属或其他化合物组成的膜系产品。其镀膜层具有对可见光高透过及对中远红外线高反射的特性:优异的热性能 普通浮法玻璃的辐射率高达0.84，当镀上一层以银为基础的低辐射薄膜后，其辐射率可降至0.1以下。 如果使用Low-E玻璃，由于热损失的降低，可大幅减少因采暖所消耗的燃料，从而减少有害气体的排放。 良好的光学性能 Low-E玻璃对太阳光中可见光有高的透射比，可达80%以上，而反射比则很低，这使其与传统的镀膜玻璃相比，光学性能大为改观。从室外观看，外观更透明、清晰，保证了建筑物良好的采光，又避免了以往大面积玻璃幕墙、中空玻璃门窗光反射所造成的光污染现象。 镀膜玻璃按产品的不同特性，可分为以下几类： 热反射玻璃、低辐射玻璃（Low-E）、导电膜玻璃等。 热反射玻璃一般是在玻璃表面镀一层或多层诸如铬、钛或不锈钢等金属或其化合物组成的薄膜，使产品呈丰富的色彩，对于可见光有适当的透射率，对红外线有较高的反射率，对紫外线有较高吸收率，因此，也称为阳光控制玻璃，主要用于建筑和玻璃幕墙； 低辐射玻璃是在玻璃表面镀由多层银、铜或锡等金属或其化合物组成的薄膜系，产品对可见光有较高的透射率，对红外线有很高的反射率，具有良好的隔热性能，主要用于建筑和汽车、船舶等交通工具，由于膜层强度较差，一般都制成中空玻璃使用； 导电膜玻璃是在玻璃表面涂敷氧化铟锡等导电薄膜，可用于玻璃的加热、除霜、除雾以及用作液晶显示屏等； 玻璃吸收能力的强弱，直接关系到玻璃对远红外热能的阻挡效果。辐射率低的玻璃不易吸收外来的热辐射能量，从而玻璃通过传导、辐射、对流所传递的热能就少，低辐射玻璃正是限制了这一部分的传热。 以上两种形式的热能透过玻璃的传递可归结为两个途径：太阳辐射直接透过传热、对流传导传热。 透过每平方米玻璃传递的总热功率Q可由下式表示： Q=630Sc+U（T内-T外）? 式中630是透过3mm透明玻璃的太阳能强度，（T内-T外）是玻璃两侧的空气温度，均是与环境有关的参数。 SC和U是玻璃自身的固有参数，其含义如下： SC———玻璃的遮阳系数，数值范围0～1，它反映玻璃对太阳直接辐射的遮蔽效果。U———玻璃的传热系数，它反映玻璃传导热量的能力。 由此可见，玻璃节能性的优劣由U和SC这两个参数就完全可以判定 三、不同玻璃的传热特性及参数 1、普通透明玻璃 透明玻璃（钠钙硅玻璃）的透射范围正好与太阳辐射光谱区域重合，因此，在透过可见光
Low-E中空玻璃在节能门窗中的应用
Low-E中空玻璃在节能门窗中的应用 鸿泰门窗:李国培门窗的节能性能指标主要有三个部分组成：窗框、玻璃以及窗框与玻璃结合部位的性能。由于高性能门窗，对影响窗框与玻璃结合部位的性能起重要作用的五金件及密封条有很高的要求，气密性都很高，因此有必要讨论对门窗的得热和失热起主要作用的玻璃系统以及Low—E中空玻璃在节能门窗应用问题。 一、门窗节能主要是认识和合理运用问题 门窗节能并不是人们想象的存在技术上的问题，更多的是我们对它们的重新认识与合理运用的问题。 近两年一些高档住宅，由于追求通透、景观好，外窗面积都设计得很大，发展商一般会采用中空玻璃，如果严寒需要采暖的地区，注重品牌的发展商在窗框材料上还会考虑选用断桥铝型材，由于窗墙比很大，从节能的角度出发，我会建议采用Low—E中空玻璃，如果考虑造价我则建议窗框材料不用断桥铝型材而改用普通铝合金与Low—E中空玻璃的搭配，但很多发展商都不愿意采用这种组合。而美国等一些发达国家恰恰相反，他们强调必须采用高性能的Low—E 中空玻璃，窗框材料则可以是普通铝型材。如果消费者有更高的要求，则选用纯木、铝包木或铝木复合等，在寒冷地区他们会要求Low—E中空玻璃充氩气等惰性气体降低U值，而较少采用断桥铝型材。为什么有这种差异呢？通过下面的对比分析也许可以找到答案。 二、不同玻璃及门窗产品性能价格比较 表一
U值按ISO10292标准测得，Sc按ISO15099测得。 仅从降低窗户传热系数的角度看，断桥铝型材与Low—E中空玻璃的组合，U值可降到2.5W/m2K或更低，但如果从我国目前的发展水平以及综合性价比，则选用普通铝合金与Low—E中空玻璃的组合是比较理想的选择，Low—E 中空玻璃充氩气后U值还可以降0.4左右而成本每平方米仅增加30元。 三、Low-E中空玻璃 1、Low—E玻璃的特性 低辐射(Low—E）玻璃之所以节能，是因为它有如下特性： a)高的反射率，红外线反射率高(可达98%)，冬季有效阻止室内暖气和人体发出的热辐射泄向室外，夏季有效阻止室外道路及建筑物等发出的热辐射进入室内，具有阻止热辐射直接透过的作用，使室内冬暖夏凉。 b)低的辐射率，玻璃对热量的吸收和辐射决定于表面辐射率，辐射率低则吸热少，升温慢，再放出的热量少。
暖边技术与中空玻璃的节能
暖边技术与中空玻璃的节能 中空玻璃由美国人托马思?司特森发明，1865年获得专利。其结构设计与今天的中空玻璃虽然有所不同，但是却很接近了。中空玻璃出现之前，人们使用的多为双层玻璃窗，由于当时窗户的气密性较差，人们不得不花一定的时间来擦洗两片玻璃之间的污物。中空玻璃的发明主要是为了迎合人们减少擦洗玻璃的劳动的需要。当时的结构为两片玻璃，中间使用绳子或木条来间隔外面采用焦泥来密封。这种中空玻璃的缺点在于密封性差，内部没有干燥剂，玻璃空腔内的空气是不干燥的。在以后的大约100年的漫长岁月里，中空玻璃的发展是十分缓慢的，只在局部结构方面得到了某些改进。从上个世纪60年代起，现代中空玻璃材料的逐步出现和广泛使用，包括铝金属间隔条、有机密封胶(从单道密封为主到今天的双道密封占主导地位)和3A分子筛，才使得中空玻璃的密封性能得到彻底的改善，形成了目前的中空玻璃结构。铝金属间隔条的应用使中空玻璃的现代生产成为可能，但另一方面，却是以牺牲中空玻璃的节能性为代价的，这是由于铝金属间隔条的导热系数大，形成能源损失的通道。为了解决中空玻璃边部的热损失问题，暖边间隔条应运而生，在发达国家得到了广泛应用。据统计，1990年冷边中空玻璃占市场份额的85％，暖边仅仅占15％，但是到了2000年，暖边上升到80％，冷边则下降到20％。 暖边概念：任何一种间隔条只要其热传导系数低于铝金属的导热系数，就可以称为暖边。暖边可以采用三种方法得到： (1)非金属材料，如超级间隔条、TPS、玻璃纤维条； (2)部分金属材料，如断桥间隔条、复合胶条； (3)低于铝金属传导系数的金属间隔条，如不锈钢间隔条。 可见发达国家有关暖边的定义是十分宽松的。由此，我们可将其按节能的性能分为以下三大类：低性能、中等性能和高性能间隔条。 (1)低性能间隔条的特点是含有部分金属或采用比铝金属导热系数低的金属。采用NFRC （美国国家门窗等级评定委员会)标准窗，低性能间隔条对整窗的U值改善程度为0．06。 (2)中等性能间隔条的特点是含有部分金属或采用比铝金属导热系数低的金属。采用NFKc(美国国家门窗等级评定委员会)标准窗，该类间隔条对整窗的U值改善程度为O．1 1。 (3)高性能间隔条的特点是采用非金属材料，因此导热系数大大低于铝金属。采用NFRC(美国国家门窗等级评定委员会)标准窗，高性能间隔条(如超级间隔条)对整窗的U值改善程度为0．2。 暖边间隔条和65％的节能标准。超级间隔条是暖边中唯一不含有金属、内含3A分子筛、具有微孔结构的弹性硅酮间隔条，不但导热系数低(仅仅为铝金属的1／950)，从而改善中空玻璃的整体节能效果，而且还有利于延长中空玻璃的密封寿命，同时提高生产效率。 北京地区从2004年7月1日起率先在全国实行65％的节能标准，对窗户要求传热系数应达到2．8W／m2?K。普通双玻中空玻璃的节能配置为，普通玻璃、槽铝式间隔条、空气，其传热系数是3w／m2?K，不能满足北京地区65％的节能标准。为达到这一要求，对普通中空玻璃的节能配置必须改进。可供选择方案如下： 1) 将普通玻璃替换成低辐射玻璃，传热系数可降低到2 W／m2?K 2) 将铝间隔条替换成超级间隔条，传热系数降低到2．8W／m2?K 3) 将空气置换成氩气，传热系数有所下降，但仍大于2．8W／m2?K
镀膜玻璃常见质量问题
一、划伤或擦伤 定义和说明：镀膜玻璃表面和其它较硬的物质相对滑动或磨擦造成的线状或带状的伤痕为划伤或擦伤，主要表现为划伤或擦伤部位的玻璃透光率增高，或膜面脱落透亮。其形态多为不规则的弧形细条状或带状。 产生原因：划伤或擦伤往往是在施工安装使用中产生的，主要有： 1、生产方面：由于设备或后清洗的原因，在生产中是存在玻璃划伤可能性的，但这种划伤一般为规则的和直线型的，是能控制和检验出来的。另外，生产过程中对镀膜玻璃的搬运、装箱也是有可能造成划伤的，原片本身也可能存在划伤。但客观的说，大片镀膜玻璃因是直接在线用装片机装片，一般是不可能造成划伤的，而强化镀膜玻璃因也是直接贴膜后装箱，膜面一般不会接触其它硬物，所以通常也是不会出现划伤或擦伤的。 2、切割原因：比如切割尺或卷尺在玻璃膜面的拖动；因玻璃膜面上有砂粒或玻璃屑等，擦拭过程中造成的玻璃膜面的擦伤；镀膜面朝下切割或没注意到每箱的最后一片是反方向放置等原因，致使玻璃膜面与它物摩擦而造成划伤。 3、堆放和存放：开箱后或切割后的玻璃没有按要求堆放，片于片之间没有垫任何衬垫物，致使玻璃之间直接接触，由于砂粒或玻璃屑等的原因，在搬运或运输过程中造成划伤或擦伤。 4、安装和清洗：在打胶或安装中，人为原因造成的因硬物的划伤或擦伤；在清洗中使用了不干净或较硬的擦拭物，或是在玻璃膜面有水泥砂浆等污染物，而使用了不正确的清洁方法。 二、掉膜 定义和说明：镀膜玻璃膜层表面出现的局部掉膜或脱膜现象。主要表现为局部的透光率增强或膜层完全脱落，脱膜形态一般是指点状、团状和片状的。对掉膜现象，在生产过程中产生的，我们都有严格的标准控制，一般来说，掉膜部位的直径大于是不允许的。 产生原因：引起掉膜的原因较多，往往也较难界定，其主要原因有： 1、生产方面：因镀膜工艺的原因，在生产中可能会出现一些针状的掉膜，也叫针眼，是溅射镀膜工艺本身无法避免的。另外，因镀膜原片本身或设备清洗的原因，也有可能造成掉膜，对此国家标准有相应的要求和规定，我们出厂的产品都是严格按此规定检验，合格后才出厂的。
中空玻璃节能性能影响因素分析
中空玻璃节能性能影响因素分析 摘要：本文通过对各种类型中空玻璃的传热系数的研究，分析了原片组合、间隔类型、使用环境等各方面的相关因素对中空玻璃节能指标的影响趋势及程度。在此基础上，探讨了建筑和生产设计中，应正确选用的、能达到最佳节能效果的中空玻璃组合方式及使用条件。 [关键词] 中空玻璃传热系数建筑节能 一、建筑节能对玻璃性能的要求 在影响建筑能耗的门窗、墙体、屋面、地面四大围护部件中，门窗的绝热性能最差，是影响室内热环境质量和建筑节能的主要因素之一。据统计，在采暖或空调的条件下，冬季单玻窗所损失的热量约占供热负荷的30%~50%，夏季因太阳辐射热透过单玻窗射入室内而消耗的冷量约占空调负荷的20%~30%。因此，增强门窗的保温隔热性能，是改善室内热环境质量和提高建筑节能水平的重要环节。 二、中空玻璃节能特性的基本指标 在建筑用中空玻璃诸多的性能指标中，能够用来判别其节能特性的主要有传热系数K和太阳得热系数SHGC。中空玻璃的传热系数K是指在稳定传热条件下，玻璃两侧空气温度差为1℃时，单位时间内通过1平方米中空玻璃的传热量，以W/m2K 表示。K值越低，说明中空玻璃的保温隔热性能越好，在使用时的节能效果越显著。太阳得热系数SHGC是指在太阳辐射相同的条件下，太阳辐射能量透过窗玻璃进入室内的量与通过相同尺寸但无玻璃的开口进入室内的太阳热量的比率。玻璃的SHGC值增大时，意味着可以有更多的太阳直射热量进入室内，减小时则将更多的太阳直射热量阻挡在室外。SHGC值对节能效果的影响是与建筑物所处的不同气候条件相联系的，通常温带地区的使用的建筑中空玻璃的节能指标主要考虑传热系数K，在这里我们主要探讨K值对中空玻璃节能的影响。 三、节能指标的影响因素分析 1、玻璃的厚度：中空玻璃的传热系数，与玻璃的热阻（玻璃的热阻为1mK/W）和玻璃厚度的乘积有着直接的联系。当增加玻璃厚度时，必然会增大该片玻璃对热量传递的阻挡能力，从而降低整个中空玻璃系统的传热系数。对具有12 mm空气间隔层的普通中空玻璃进行计算，当两片玻璃都为3mm白玻时，K=2.745W/m2K，都为10mm白玻时，K=2.64 W/m2K，降低了3.8%左右，且K
相关文档
- ASTM C 1048-04热处理平板玻璃标准规范-HS类、FT类镀膜和非镀膜玻璃
- 镀膜玻璃国内外标准讲解
- 镀膜玻璃国内外标准
- 镀膜玻璃检验规则
- Lowe玻璃和镀膜玻璃
- 低辐射镀膜玻璃(Low-E玻璃)性能
- 镀膜玻璃基础知识培训
- 建筑玻璃系列的国家标准
- 镀膜玻璃 第2部分：低辐射镀膜玻璃(标准状态：被代替)
- 镀膜玻璃 第1部分：阳光控制镀膜玻璃(标准状态：被代替)
- 镀膜玻璃知识
- (整理)低辐射镀膜玻璃标准.
- 镀膜玻璃国家标准英文版
- 镀膜玻璃耐候性的分析
- 镀膜玻璃性能参数介绍
- 镀膜玻璃常见质量问题
- ASTM JIS EN与中国国家标准对比详细情况(钢化镀膜中空(xiugai))解析
- 镀膜玻璃常见质量问题
- 什么是Low-E镀膜玻璃
- 镀膜玻璃的几种方法