Nejnavštěvovanější odborný web
pro stavebnictví a technická zařízení budov
estav.tvnový videoportál

TZB-info - Gateway to the world of specialized information

TZB-info is an Internet resource specialising in information on construction, energy savings, and the related fields collectively referred to as mechanical and electrical systems usually known as building services (in Czech abbreviated as TZB). Its primary focus lies within the construction of buildings and energy issues related thereto. Whether you're looking for heating, electricity, heat loss reduction or building efficiency, the portal offers up-to-date information on the developments in those fields every day. The information presented by TZB-info is carefully selected and edited, serving a diverse audience of professionals ranging from designers to installers but also the general public. TZB-info records 750,000 visits every month. read whole text

Latest reviewed editorial research papers in the field of building services engineering

Heating

Novinky v normách pro komíny

26.5.2025 | Ing. Jiří Vrba, TNK 105 Komíny
Heating

Jak si pohlídat kvalitu vrtu pro tepelné čerpadlo

12.5.2025 | Ing. Josef Hodboď, TZB-info, redakce
Ventilating and Air-Conditioning

Practical experience in cleaning ventilation systems in family houses

12.11.2024 | Ing. Pavla Skalická, Luftuj s.r.o., časopis VVI, 2/2024 | Vytápění větrání instalace, 2/2024
Practical experience with the cleanability of parts of the forced ventilation system with heat recovery in family houses. The need for cleaning and design and assembly deficiencies that lead to difficult maintenance. Some policies to make service easier.
Water and Drainage

Mikrobiologická problematika užitkové a pitné vody v době povodní

19.6.2025 | RNDr. Dana Baudišová, Ph.D., Státní zdravotní ústav ČR
Water and Drainage

Okrajové podmínky návrhu zásobníku teplé vody z pohledu typu zdroje tepla

10.4.2025 | Ing. Roman Vavřička, Ph.D., ČVUT v Praze, Fakulta strojní, Ústav techniky prostředí, Univerzitní centrum energeticky efektivních budov ČVUT v Praze
Water and Drainage

Vodní audity průmyslových podniků

28.3.2025 | Ing. Žaneta Ťopková, Ing. Jana Křivánková, Ph.D.
Water and Drainage

History and Present of Water Treatment Plants in Slovakia

12.3.2025 | prof. Ing. Danka Barloková, PhD., prof. Ing. Ján Ilavský, PhD.
The first water treatment plants in Slovakia were built in the 1930s for the purpose of obtaining high-quality drinking water. The article provides an overview of water treatment plants and technologies used in water treatment during their existence. The total number of treatment plants that have been put into operation is 138, with a capacity from 1 l/s to 1000 l/s of treated water. Currently, 80 of this number are in operation, 14 of which have been reconstructed, not only the building part, but also the technological equipment has been replaced with newer, more efficient ones so that the treated water meets the requirements for drinking water set by the Decree of the Ministry of Health of the Slovak Republic No. 91/2023 Coll., which establishes details on the quality of drinking water, drinking water quality control, monitoring program and risk management in drinking water supply.
Renewable Energy

Kyberbezpečnost (nejen) solárních elektráren: Rekapitulace zásadních událostí letošního jara

4.6.2025 | Ing. Erika Langerová, ČVUT v Praze, Univerzitní centrum energeticky efektivních budov
Renewable Energy

Digitalizace domácího vytápění a fotovoltaiky – jaké jsou kyberbezpečnostní výzvy?

29.4.2025 | Ing. Erika Langerová, ČVUT v Praze, Univerzitní centrum energeticky efektivních budov
Renewable Energy

Jak si nenechat hacknout solární elektrárnu. Část 1: domácí fotovoltaika

22.4.2025 | Ing. Erika Langerová, ČVUT v Praze, Univerzitní centrum energeticky efektivních budov
Electrical Engineering

Nedostatečná úroveň kyberbezpečnosti solárních elektráren: první incidenty a role Číny

25.2.2025 | Ing. Erika Langerová, ČVUT v Praze, Univerzitní centrum energeticky efektivních budov
Electrical Engineering

Metody pro 3D skenování historických hliněných staveb

16.12.2024 | Ing. Jan Müller, Ph.D., Mgr. Martin Novotný, Ph.D.
Foto © luchschenF, Fotolia.comElectrical Engineering

A True Digital Transformation of the Company and a Unified Integrated Operating Environment

2.4.2024 | Ing. Jiří Holoubek, prezident Elektrotechnická asociace České republiky
IT systems in companies are often incompatible and their data communication is very complicated. A unified, integrated operating environment ensures real online communication not only of technological devices, but also technology for quality monitoring, systems for order planning, service and maintenance, as well as energy management.
Electrical Engineering

Fiber-optic FBG Sensors

25.1.2021 | Ing. Radim Šifta, Ph.D., NETWORK GROUP, s.r.o.
The paper describes special types of fiber optic point sensors based on FBG (Fiber Bragg Grating) and FP (Fabry-Perót) structures. First part of the paper deals with principle of FBG and FP and their exposition. Next part is focused on different types of FBG and FP sensors and principle of interrogation units. Finally practical examples of use are listed.
Elevators

Provozní prohlídky výtahů

24.8.2015 | Ing. Bohuslav Kratěna, Unie výtahového průmyslu České republiky
Elevators

Poznatky z prověřování (auditu) firem provádějících servis na výtazích

20.7.2015 | Vladimír Hulena, pověřený HK ČR k provádění auditu
CSN 27 4002 2014 Safety rules for lifts - Operation and service of lifts has introduced a new term by an authorized service company. It is the transparency of professional competence companies in servicing elevators, to owners / operators can better decide with whom an agreement that service because it has a major impact on their responsibility to ensure the safe operation of elevators. Therefore, for this situation was the subject of speculation, it was decided to examine service firms independent commissioners, contracted authorizing body, in this case, the Chamber of Commerce, which, when positive evaluation subsequently issue a certificate of authorization, and the company name may Authorized service company use.
VýtahElevators

News in the standards and audits for elevator industry

28.7.2014 | Ing. Jan Dvořák, Ing. Bohuslav Kratěna, Vladimír Hulena
Union for Elevator Industry summarizes the most important news in the standards and audits, as presented at the seminar Elevators 2014. This includes controversy with a new concept of authorized service company that has been published on our portal in advance.
Zákaz používání výtahu za požáru - výtah neslouží k evakuaci osobElevators

Standards in the projects in terms of fire safety of elevators

21.7.2014 | plk. Ing. Zdeněk Hošek, Ph.D., Ministerstvo vnitra - generální ředitelství Hasičského záchranného sboru ČR
Elevators belong to a very important building services and technologies. For these reasons, they need to pay attention not only in terms of proper technical implementation, but also in terms of fire safety. In particular, fire and evacuation lifts, which are also very important fire safety devices must also meet the stringent technical requirements of fire protection.
Chybějící kotvení nebo ochrany rohů – snížení odolnosti při nárazu. Závady regálů ve skladu. Zdroj: www:efameco.czFacility management

Safety of Rack Systems in Warehouses

30.6.2025 | Vladimír Baletka, jednatel společnosti eFAMECO s.r.o.
The article “Safety of Rack Systems in Warehouses” deals with key aspects of safety when using rack systems in warehouses. It emphasizes the importance of regular inspections and maintenance of rack structures to prevent accidents and injuries. Furthermore, it addresses legislative requirements and standards that must be followed to ensure the safety of workers and stored materials. The article also provides practical advice and recommendations for the proper use of rack systems, including correct loading and organization of stored items.
Facility management

Porovnání energetických konceptů zásobování obce teplem v projektu Cérka

29.5.2025 | doc. Ing. Tomáš Matuška, Ph.D., Ing. Nikola Pokorný, Ph.D., Ing. Jiří Novotný
The article presents a study focused on the analysis of the potential use of renewable heat within the Cérka project, which aims to revitalize the area of the unused Frenštát mine in Trojanovice. It presents the basic characteristics of the compared systems, including an evaluation of annual usage and the estimated cost of heat.
Facility management

Why Maintaining the Accessibility of Escape Routes Is Critical: Practical Consequences of Non-Compliance with Fire Safety Requirements

14.5.2025 | Vladimír Baletka, jednatel společnosti eFAMECO s.r.o.
This article addresses a crucial aspect of fire safety in buildings – the accessibility and unobstructed condition of escape routes. Based on real-world examples, it highlights severe deficiencies such as incorrectly mounted fire doors, missing door closers, and the placement of combustible furniture in protected escape routes. The text explains the applicable legal and technical requirements (e.g., Decrees No. 23/2008 Coll., 202/1999 Coll., Government Regulation No. 101/2005 Coll., and ČSN 73 0835) and provides practical recommendations for facility managers, building administrators, and fire safety professionals. The aim is to reduce evacuation risks and ensure compliance with fire safety legislation.

RECENT REVIEWED EDITORIAL RESEARCH PAPERS IN THE FIELD OF BUILDING SERVICES ENGINEERING


Heating | Ventilating and Air-Conditioning | Water and Drainage | Renewable Energy | Electrical Engineering | Energetics

Latest reviewed editorial research papers in the field of construction

Shell Construction

Repair Plasters for Historical Buildings Applied During the 20th and early 21st Centuries – Part 1

30.6.2025 | prof. RNDr. Pavla Rovnaníková, CSc.,, VUT FAST v Brně, Ústav chemie
This article focuses on the composition and restoration of plasters of historical buildings, carried out since the 20th century, especially from its second half until today. The binders, admixtures, and additives used for plasters in the past are described, and the differences in their properties compared to those of current materials are discussed. The principles of plaster restoration using various methods of preparing plaster mortar mixtures are described. Attention is also paid to the types and properties of plasters for damp masonry containing water-soluble salts. Disagreeing opinions on restoration from the perspective of architectural heritage care and technologists are also discussed.
Shell Construction

Navrhování ocelových stavebních konstrukcí pro opětovné využití

23.6.2025 | prof. Ing. František Wald, CSc., Ing. Břetislav Židlický, Ph.D.
Contemporary construction emphasizes minimizing the impact of industrial production on the environment and preventing waste generation. This approach opens up space for meaningful objectives, such as reusing building structures and their elements - a practice that has been common for centuries. Today's goals can be achieved particularly by restoring and circulating existing structural elements, both in construction and other industrial sectors - without the need for their separation or recycling into basic materials. These processes are now feasible due to advanced industrial technologies and efficient supply chains. The contribution is based on materials from the ADVANCE project and a seminar by the Department of Steel Structures at CTU in Prague.
Shell Construction

Zatížení větrem pro dočasné konstrukce

16.6.2025 | doc. Dr. Ing. Jakub Dolejš, Ing. Břetislav Židlický, Ph.D.
According to the applicable legal framework, scaffolding is not classified as a building structure, but rather as one of the so-called listed products. This means, among other things, that there are specific standards that apply to them, whether focused on execution, inspection, or the design itself. We offer designers two possible procedures.
Shell Construction

MNC spoje dřevěných konstrukcí vystavené opakovanému namáhání

19.5.2025 | prof. Ing. Antonín Lokaj, Ph.D., Ing. Pavel Dobeš, Ph.D., Ing. Marek Johanides, Ph.D., Ing. David Mikolášek, Ph.D.
The article deals with the experimental analysis of MNC (Multiple Nail Connectors) joints of wooden elements. In laboratory tests, samples of MNC joints of wooden elements were analyzed under quasit-static and cyclic tensile loading parallel to the grain. The elements of the tested joints were made of structural timber C24, glued laminated timber GL24h, and laminated veneer lumber (LVL Ultralam-R). The experimental results were then compared with a numerical model in SCIA Engineer and with analytical calculations according to applicable standards.
Insulation, Roofs, Facades

Typické historické krovové systémy

4.5.2025 | Ing. Silvia Martinkovičová, Ing. Ján Brodniansky, PhD., Ing. Pavel Vonšovský, Dis., Ing. Jiří Bláha, Ph.D.
Insulation, Roofs, Facades

Loft Extensions and Superstructures in Masonry Buildings (Part 1)

28.4.2025 | doc. Ing. Jaroslav Solař, Ph.D., VŠB TU Ostrava, Fakulta stavební, katedra pozemního stavitelství
This paper begins the first part of a series of articles on the design of loft extensions and superstructures in masonry buildings. The first part deals with the problem of loading of floor structures and the possibilities of further action in cases where the floor structure is structurally unsuitable for the new purpose. Subsequently, the possibilities of increasing the load-bearing capacity of wooden ceilings are described. This is done by changing the structural system, inserting a new ceiling slab, and by coupling the original ceiling with an additional structure.
Insulation, Roofs, Facades

Statická analýza historických krovových systémov

27.4.2025 | Ing. Silvia Martinkovičová, Ing. Ján Brodniansky, PhD., Ing. Pavel Vonšovský, Dis., Ing. Jiří Bláha, Ph.D.
Insulation, Roofs, Facades

Rekonštrukcie strechy bytového domu a autorský dozor

10.4.2025 | Ing. Peter Juráš, PhD., Stavebná fakulta Žilinskej univerzity, Katedra pozemného stavite
Windows, Doors

Bonded Joints of Glass Structures

23.12.2024 | Ing. Jakub Mareš, Ing. Yasmina Boutar, Ph.D., prof. Ing. Martina Eliášová, CSc.
This paper presents the results of an experimental investigation into fully transparent bonded joints for load-bearing glass structures. The research specifically focused on the surface properties of glass that affect the load-bearing capacity of the joints, such as surface energy, wettability, and roughness. It also discusses the differences between the tin and air sides of the glass sheets.
The findings are supported by tests conducted at the Faculty of Civil Engineering at CTU between 2021 and 2023. Tensile and dynamic tests of the selected adhesive LOCTITE® EA 9455 as well as shear tests of single-shear glass-to-glass joints, were evaluated, with a focus on the load-bearing capacity of the joints at elevated temperatures.
The paper concludes with a summary of the results and suggests their implications for engineering practice.
Windows, Doors

Principles of Installation and Drawing Opening Fillers - Part 2: Doors

16.9.2024 | Ing. Zuzana Rácová, Ph.D., Ing. Aneta Libecajtová, Ph.D.
The article focused on the issue of installing door panels in interior vertical load-bearing and partition structures. The paper presents selected types of door panels primarily used in apartments and family houses, describes the principles of their installation, and their depiction in drawing documentation in accordance with the ČSN 01 3420 standard for drawing construction parts. It is necessary to correctly and clearly apply the rules of the standard to the depiction of currently used door panels.
Windows, Doors

Principy osazování a zakreslování otvorových výplní – Díl 1: Okna

8.4.2024 | Ing. Zuzana Rácová, Ph.D., Ing. Aneta Libecajtová, Ph.D.
The article is focused on the issue of installing windows in external walls and their drawing in accordance with the standard ČSN 01 3420 Construction drawings - Presentation of general arrangement drawings. The paper highlights the obsolescence of previous solutions in light of current requirements for the energy efficiency of buildings and technological advancements in construction. Specifically, it is focused on the principles of installing opening fillings, including thermal and technical requirements, and technological aspects. It is shown that incorporating new technological processes and energy efficiency requirements necessitates reflecting these changes in the project documentation as well. Furthermore, the article addresses the depiction of current solutions in construction practice in accordance with the ČSN 01 3420 standard at scales of 1:50 and 1:20.
Foto ©Ingo Bartussek - Fotolia.comWindows, Doors

Thermal Properties of Double Window and Modern Construcions Jamb

20.3.2023 | Ing. Lucie Kudrnáčová, Ph.D, ČVUT v Praze, Kloknerův ústav, Oddělení stavebních materiálů
The paper deals with the comparison of the thermal properties of jamb for different types of windows. In the case of reconstruction, it is often necessary to preserve the original double- windows or to use modern materials due to the thermal solution of the building. Modern constructions mean the use of double or single windows with thermal-insulating glazing. These changes in the construction of the window have an effect on the thermal processes on the structure. One of the important parameters for the assessment of the building structure is the assessment of the internal surface temperature of the building structure. This article shows the difference in finishes and heat flows to remove different types of windows. The reference window for comparison is the original double history window. The results were found in a model environment in 2D software.
Low Energy Buildings

EPBD IV.: Transformace bytového domu na budovu s téměř nulovými emisemi CO2

21.4.2025 | Ing. Veronika Dokoupilová, doc. Ing. Petr Horák, Ph.D.
Preparations for the implementation of the EPBD IV directive, i.e. the transition to nearly zero-emission buildings, into Czech legislation are underway. The results of the study indicate options leading to compliance with EPBD IV in an apartment building.
Zlatý certifikát SBToolCZLow Energy Buildings

SBToolCZ. The Latest Online Version of the National Building Sustainability Assessment Methodology

6.2.2023 | Ing. Kateřina Klepačová, Ing. Magdaléna Novotná, Ph.D., Ing. Martin Volf, Ph.D., Ing. Jakub Diviš, Ph.D., Ing. Jan Růžička, Ph.D.
ilustrační foto: Main Point Karlín © TZB-infoLow Energy Buildings

Environmental Certification of Buildings - the Situation in the Czech Republic

30.4.2021 | Ing. Zuzana Mrňová, VUT FAST Brno, Ústav stavební ekonomiky a řízení
A responsible approach to the environment is not only related to corporate ecology, but is also increasingly reflected in the design and construction of buildings, which is closely related to the concept of sustainable construction of buildings. With the development of sustainable construction, the need arose to evaluate buildings and their impact on the environment. For this reason, environmental certifications of buildings have been developed, which assess how a building affects its surroundings during its life cycle.
The aim of this article is to find out which environmental certifications exist in the world and which of them are most often used in the Czech Republic. Finally, the certifications are compared and their main differences are described.
ilustrační obrázek © starush - Fotolia.comLow Energy Buildings

Stavebně-energetické koncepce budov ve společenských souvislostech

8.2.2021 | prof. Ing. Jan Tywoniak, CSc., ČVUT v Praze | Dřevo&Stavby Profispeciál 2020
Wooden Buildings

Aktuální stav technické normalizace pro dřevostavby

9.6.2025 | doc. Ing. Petr Kuklík, CSc., Ing. arch. Bc. Anna Gregorová
Although the term wooden construction is not introduced in our legal regulations, we commonly understand this term as constructions in which wood and wood-based products are the main material used. However, the proportion of wood and wood-based products is not defined and depends on the construction system used. Wooden constructions are currently the subject of growing interest among developers, architects, civil engineers and the public. This is mainly due to the fact that they offer an alternative method of building construction with great ecological benefits. Their advantage is also the speed of construction and usually low demands on the equipment of the construction site. Technical standards are important for their design and implementation.
Wooden Buildings

Přínos 2. generace Eurokódu 5 pro navrhování dřevostaveb

8.7.2024 | doc. Ing. Petr Kuklík, CSc., Ing. arch. Bc. Anna Gregorová
Wood buildings, i.e. buildings in which wood and wood-based products are the dominant material used, are currently the subject of growing interest among developers and the professional public. This is mainly due to the fact that they offer an alternative way of constructing safe buildings with great environmental benefits. The prerequisites for their greater implementation are then created by new versions of European standards. In this paper some new procedures for their design according to the 2nd generation of Eurocode 5 are presented.
Wooden Buildings

Vývoj konstrukčního řešení prefabrikovaného rámového systému pro dřevostavby

18.12.2023 | Ing. Martin Hataj, Ph.D., Ing. Jan Pošta, Ph.D., Ing. Pavla Novotná
Within the framework of the project "Prefabricated recyclable timber-based frame building system", a new building system is being developed, the main load-bearing elements of which are rigid frames made of timber-based material. The principal investigator of the project is ecokit s.r.o. and the co-principal investigator is UCEEB CTU. This paper presents the development of the load-bearing structure of the frame system.
Wooden Buildings

Ochrana dřeva, trvanlivost povrchové úpravy dřevěných fasád a teras

2.10.2023 | Ing. Petr Ptáček, Ph.D., ČVUT v Praze, pracoviště UCEEB
The protection of wood in wooden buildings does not seem to be very important due to their location in use class 1 or 2 according to ČSN EN 335, but it is particularly suitable for timber elements that are located close to the foundation slab or are difficult to replace. It follows from the majority of recurring defects, for example plumbing failures, leaks through the roof, facade, inappropriate terrain height around the base plate or as a result of a tornado, that it is necessary to protect at least the foundation threshold according to the structure of the wooden building, preferably up to use class 4 according to ČSN EN 335, which is only possible by pressure impregnation.
Building Regeneration

Nejčastější statické problémy historických cihelných objektů

20.10.2024 | Ing. Jan Zima, Rekonstrukce památkových objektů-atelier statiky spol. s r.o.
Building Regeneration

Non-destructive Determination of Building Stone Provenance

26.8.2024 | Mgr. Kateřina Kovářová MBA, Ph.D,, Ing. Eva Matoušková, Ph.D.
In our practice, we often face the question of building stone provenance on historic buildings. However, methods providing relevant answers to this question are mostly of a destructive character requiring sampling. Therefore, our research has focused on the use of reflectance spectrometry, which is a very promising and effective non-destructive method. This paper discusses the basic principles and possibilities of this method with regard to its application to historic buildings and decorative stone.
Building Regeneration

An Example of the Use of Available IT Technologies During the Renovation of the Castle in Nemysl

8.4.2024 | Ing. Denisa Boháčová, Ph.D., prof. Ing. Pavel Kuklík, CSc.
The paper presents the original condition of the castle in Nemyšl near Tábor together with the subsequent process of its rehabilitation. This requires a careful evaluation of its condition, determination of the remediation procedure along with condition monitoring to ensure safety on the construction site. To accomplish this task - the abbreviation SHM (Structural Health Monitoring) is used abroad - the available possibilities of current information technologies have been used.
Building Regeneration

Current Civil Engineering Activities Contributing to the Reliability and Sustainability of Historical Monuments

1.4.2024 | Ing. Denisa Boháčová, Ph.D., prof. Ing. Pavel Kuklík, CSc.
The paper deals with the role of engineers in the contemporary world. In particular, it is focused on presenting the current possibilities in preserving historical monuments and their maintenance. In two case studies, point out the new possibilities offered by computer technology and connecting the involved actors through the web. It also mentions the WEC 2023 World Engineering Convention in a certain way. Due to the scale, the first, general part is presented first, which is supplemented by the concept verification while monitoring the retaining wall of St. James Church in Nepomuk. In the following separate paper, an example of the use of these technologies in the rehabilitation of the castle in Nemyšl is presented in more detail.
Building Physics

K novému znění ČSN 73 0540-2 Tepelná ochrana budov

5.6.2025 | prof. Ing. Jan Tywoniak, CSc., ČVUT v Praze
The contribution briefly comments on the changes in the newly processed wording of ČSN 73 0540-2 Thermal Protection of Buildings. Part 2: Requirements (2025). It deals with the assessment of heat transfer, moisture assessment of external structures when using moisture-sensitive materials, and the assessment of surface temperatures. The greatest attention is paid to the assessment of built-in structures with low thermal inertia, such as infill elements and lightweight facades. It also addresses the assessment of airtightness, assessment of floors, and thermal stability of rooms.
Building Physics

Studie proslunění čtyř budov v ulici Jeseniova

7.4.2025 | doc. Ing. Jan Kaňka, Ph.D., člen TNK 76 Osvětlení, ČKAIT Praha
The complex of four residential buildings of the Jeseniova Residence is often cited as an example of the alleged absurdity of the requirements for sunlight in apartments. The study documents in detail the state of sunlight in this complex, located on Jeseniova Street in Prague's Žižkov district.
Building Physics

Daylighting in a Dwelling Room Lit by a Window with an Area Equal to 10% of the Room Floor Area

21.10.2024 | Ing. et Ing. Lenka Gábrová, Ph.D., Mendelova univerzita, Lesnická a dřevařská fakulta, Ústav nauky o dřevě a dřevařských technologiích
The Prague and Brno Building Regulations approved in 2024 no longer require compliance with daylighting requirements in dwelling rooms in buildings with a closed or semi-closed construction line. In these buildings, it should be sufficient to prove that the window area is at least one tenth of the room floor area. The paper deals with the daylighting evaluation in differently obstructed rooms whose window area is exactly 10% of the room floor area.
Building Physics

Činitel jasu a činitel odrazu světla ve výpočtech denního osvětlení

12.2.2024 | doc. Ing. Jan Kaňka, Ph.D., člen TNK 76 Osvětlení, ČKAIT Praha
When calculating the daylighting of buildings, the properties of shading obstacles are expressed either by means of a brightness factor or by means of a light reflection factor. The article reports on the relationship between these two factors and offers the JAFAS 2024 program to calculate the brightness factor in a simple urban situation.

RECENT REVIEWED EDITORIAL RESEARCH PAPERS IN THE FIELD OF CONSTRUCTION


Shell Construction | Insulation, Roofs, Facades | Windows, Doors | Floors, Partition Walls, Surfaces | Low Energy Buildings | Wooden Buildings | Building Regeneration | Building Physics
 
 
Reklama