STR 2.01.07:2003 – Lithuanian Building Technical Regulation for Noise Protection
The Statybos techninis reglamentas STR 2.01.07:2003 (Construction Technical Regulation), titled Pastatų vidaus ir išorės aplinkos apsauga nuo triukšmo (Protection of Internal and External Building Environments from Noise), is a mandatory legal instrument issued by the Ministry of Environment of the Republic of Lithuania. This document, in its consolidated version effective from November 1, 2024, establishes the technical framework for acoustic quality in buildings. It operates under the authority of the Lietuvos Respublikos statybos įstatymas (Law on Construction) and aligns with EU Regulation No. 305/2011 regarding essential building requirements for noise protection.
The regulation defines the acoustic comfort system through five sound classes—Class A, Class B, Class C, Class D, and Class E—based on metrics such as airborne sound insulation, impact sound insulation, reverberation time, and environmental noise levels. Its scope includes newly designed buildings, reconstructions, and major repairs across various categories: residential (single-family and multi-family), medical facilities, educational institutions, administrative buildings, and hospitality structures like hotels and motels. It also specifies the mandatory minimum performance levels, such as the requirement for new multi-family dwellings to meet at least Class C standards.
Structured into nine chapters and additional annexes, the document provides detailed classification tables and measurement methodologies. It mandates the use of accredited laboratories for in-situ acoustic testing and defines the responsibilities of developers, designers, and state institutions in ensuring compliance with the specified acoustic indicators.
Sound Classification System
The regulation classifies the acoustic environment into five distinct comfort levels. Each class represents a specific degree of protection from internal and external noise sources:
- Class A: Represents exceptional acoustic comfort conditions.
- Class B: Indicates improved acoustic comfort conditions.
- Class C: Defined as the acceptable acoustic comfort level.
- Class D: Indicates insufficient acoustic comfort conditions.
- Class E: Represents the limit or marginal acoustic comfort level.
- Unclassified (Neklasifikuojama): A special category for building exteriors where the acoustic environment may complicate the fulfillment of noise protection requirements.
Mandatory Compliance and Application
Compliance with specific sound classes is determined by the building type and the nature of the construction activity as defined in Chapter I:
- New Multi-family Dwellings: Must achieve a minimum of Class C internal acoustic comfort.
- Single-family Dwellings: Designed according to the owner's request but cannot be lower than Class E.
- Reconstructions and Major Repairs: If the building's purpose remains unchanged, the acoustic quality must not deteriorate and must meet at least Class E requirements.
- Change of Use: If a building's purpose is changed, it must meet the Class C requirements applicable to its new designation.
- Hospitality: Specific star-rated hotels are linked to recommended sound classes (e.g., 5-star hotels recommended for Class A).
Acoustic Indicators and Measurement Methods
Technical compliance is verified through specific standardized indicators measured in decibels (dB) or seconds (s) as detailed in Chapter III and V:
- Airborne Sound Insulation (R'w or DnT,w): Measures the ability of partitions and floors to reduce sound transmitted through the air.
- Impact Sound Insulation (L'n,w): Evaluates the transmission of impact noise, such as footsteps, through floor structures.
- Reverberation Time (T60): Limits the duration of sound reflection in common areas, such as stairwells and corridors.
- Environmental Noise Indicators (Ldvn): Used to classify the external environment based on day-evening-night noise levels.
Before a building is recognized as fit for use, in-situ acoustic measurements must be conducted by laboratories accredited according to LST EN ISO/IEC 17025. Measurements must cover at least 5% of building elements (with a minimum of three elements) to confirm the actual sound class.
Requirements for Building Components
The regulation provides laboratory-based classification for individual components like windows and doors (Chapter VII):
- Window and Door Sound Insulation: Classified from A to E based on their measured Rw index.
- Class A Components: Require an Rw value greater than 43 dB.
- Class E Components: Require an Rw value between 21 and 26 dB.
Frequently Asked Questions
What is the minimum mandatory sound class for new apartment buildings in Lithuania?
Newly designed multi-family residential buildings must meet a minimum requirement of Class C for the internal acoustic environment.
How many building elements must be tested for acoustic compliance?
Acoustic measurements must be performed on at least 5% of the building's elements or partitions, with a minimum requirement of three measurements per building type.
What happens to sound class requirements when a building's purpose is changed?
When the purpose of a building or specific premises is changed, the noise protection quality must meet the requirements of Class C for the new purpose.
Who is authorized to perform acoustic measurements for building classification?
Measurements must be conducted by laboratories accredited by the National Accreditation Bureau according to the LST EN ISO/IEC 17025 standard.
Which sound class is recommended for a 5-star hotel?
According to the regulation, Class A is the recommended acoustic comfort level for 5-star hotels and motels.
What does the Ldvn index represent in environmental noise assessment?
It is the day-evening-night noise indicator that describes the total noise annoyance caused by transportation sources over a 24-hour period.
Is there a minimum sound class for single-family houses?
Yes, while the owner can choose a higher class, single-family dwellings cannot be designed for a sound class lower than Class E.
What must be included in an Acoustic Classification Protocol?
The protocol must include the internal and external sound classes, date of testing, reference to STR 2.01.05:2003, construction completion year, and the accredited laboratory's details.
