E-ilf-b-c11-arc-spc-0002 R03

14ACOUSTIC ISSUES

14.1Noise/BHP

At the operating stage, the Metro train traffic shall take place under the ground; passing trains shall not produce direct noise emission to the environment. A potential source of noise can be the air intake and exhaust shafts in the basic ventilation rooms, as well as exhausts shafts of local ventilation rooms servicing the rooms located within the station area. The source of noise can also be a cooling device located in ventilation shafts.

Currently the acoustic conditions in the area of the C11 station are formed under the influence of street noise. In accordance with the acoustic map of Warsaw the LDWN[daily-evening-night] noise level in the area of the fragment is approx. 75 dB.

The types of areas subject to acoustic protection are defined in the Act of April 27th, 2001 on Environmental Protection Law, uniform text, Dz. U.[Journal of Laws] of 2008 No. 25, pos. 150, as amended. The permissible noise levels in the environment, caused by particular groups of noise sources, were defined in the Decree of the Minister of Environment of June 14th 2007 on permissible levels of noise in the environment, Dz. U. [Journal of Laws] No. 120, pos. 826. Permissible values of noise level are expressed by L_Aeq D and L_Aeq N indices, adequately for the period of a day (6 a.m. - 10 p.m.) and night (10 p.m. - 6 a.m.). The admissible values depend on both the source of noise and the nature of the area exposed to noise. Two basic groups of sources of noise have been identified: roads or railway lines; and other facilities and activities being a source of noise. In the discussed case the external acting sources related to technical equipment and exploitation of the designed Metro station should be classified as the group "including other facilities and activities being the source of noise". As regards that group, acoustic condition calculations take into account the reference time equal to 8 least favourable consecutive hours at daytime and 1 least favourable hour at night-time. The permissible values applicable in the case of noise related to operation of the Metro Warsaw line II have been presented in Table 1.

Table 1. Permissible noise levels in the environment.

No.	Intended use of land	day	night
		LAeq D	LAeq N
1	“A” health resort protection zone Hospital complexes outside the city	45 dB	40 dB
2	Single-family residential development areas Areas related to permanent residence or temporary stay of children and youth ^1) Nursing homes areas Hospitals within city limits	50 dB	40 dB
3	Multi-family residential development and boarding house areas Farmstead grounds Recreational areas^1) Residential and retail areas	55 dB	45 dB
4	Areas in the centre zone of the cities with over 100,000 inhabitants^2)	55 dB	45 dB
^1) If the areas are not used in accordance with their function at night, the permissible noise level during the night does not apply. ^2) Central city zone in the cities with more than 100,000 inhabitants is a dense residential development area with concentration of administrative, business and service facilities. In the case of cities with districts where the number of inhabitants is more than 100,000 it is possible to determine a central zone, if it is characterized by dense residential development, with concentration of administrative, business and service facilities.

The areas not listed in the Act of the Law of Environmental Protection and the Regulations are not subject to the protection against noise. In the area of C11 station, the current Local Area Plan includes only the area situated in the vicinity of PKiN, delimited with Marszałkowska, Świętokrzyska, E. Plater Streets and Jerozolimske Avenue. In accordance with the Plan, there is a park greenery and seasonal open-air café area (ZP/Us code) in the direct vicinity of the intake-exhaust structure. There is no Local Area Plan in force for the remaining grounds. As of now, the closest residential building is located over 70 m from the air intake-exhaust shaft. Permissible noise level for residential development grounds is 55 dB at daytime and 45 dB at night-time, whereas for park greenery grounds – 55 dB at daytime.

At the same time, the impact of the main fan house and other devices emitting noise outside cannot cause that the permissible noise level, as applicable inside the rooms located in the neighbouring buildings, will be exceeded. Those values are specified by the Polish PN-87/B-02151/02 Building Acoustics standard. Protection against noise in premises inside buildings. Permissible noise level in premises (Table 2).

Table 2. Permissible “A” level of noise produced by the Metro technical equipment penetrating premises in vicinal buildings.

Intended use of premises	Equivalent “A” sound level, dB		Maximum “A” sound level at transient noise, dB
	day	night	day	night
Living areas in residential buildings	35	25	40	30
Kitchens and sanitary premises in apartments	40	40	45	45
Administrative premises without internal sources of noise	35	-	40	-
Administration premises with internal sources of noise	40	-	45	-
Café and restaurant premises	45	-	-	-
Shopping areas	45	-	-	-

The requirements apply to fully furnished (equipped) premises in accordance with their intended use, with windows and doors closed. As regards public utility buildings the equivalent noise level valuation period shall be the actual period of the premises' intended use by a given group of people.

The noise level emitted into the environment was calculated using the IMMI computer software which enables forecasting in accordance with the Directive 2002/49/EC of the European Parliament and of the Council of 25 June 2002 relating to the assessment and management of environmental noise, official Journal of the European Communities L 189/12 and Commission recommendation C(2003)2807 concerning the guidelines on the revised interim computation methods for industrial noise, aircraft noise, road traffic and railway noise, and related emission data. The intake and exhaust field facilities have been modelled as a noise source pursuant to the standard PN-EN 12354-4. Building acoustics, determining acoustic values for buildings on the basis of component properties of the elements; part 4, noise penetration from a building into the environment.

In accordance with the design plans for the Metro line II there are three variants of the basic ventilation system functioning:

a) normal operating conditions with no airflow forced, ventilators not working and not emitting sound (airflow ensured by passing trains working as pistons);

b) normal operating conditions with airflow forced, ventilators working with limited capacity and emitting limited level sound (in the Ventilation Shaft one ventilator working at low rpm and at 30% of maximum capacity at most);

c) emergency conditions; in case of fire all ventilators working at full capacity and emitting noise at maximum level.

As regards acoustic calculations, it is assumed that requirements concerning environmental protection against noise shall be fulfilled in normal operating conditions. Emergency conditions (fire) is an exceptional situation that might not even occur and thus using acoustic protections adapted for emergency conditions is irrational.

During the exploitation phase the Metro will also be functioning in certain periods of the night - this applies to trains and operation of technical equipment, including air intake-exhaust shafts in the main fan houses and exhaust shafts in the local fan houses. The calculations took into account functioning of the station ventilation and other, smaller ventilation rooms equipped with external chutes. The fans and ventilation centres will be equipped with acoustic mufflers. The calculations do not account for operation of the local fire ventilation for rooms located in the technical zone and the general-access zone.

The air intake and exhaust shaft is located within the roadway, the ventilation openings are located in side walls, with the opening bottom edge at 2.5 m height above the ground level. Location of the noise sources is shown in Figure 1. During the present design stage acoustic parameters for fans are not known for the purposes of calculating noise emission into the environment and thus the maximum noise level inside the intake-exhaust shaft has been assumed as follows;

Air intake and exhaust shaft of the station fan house L_Aeq = 65 dB

As for small local fan houses, the level of acoustic power assumed for each exhaust shaft L_WA = 70 dB.

The assumed acoustic parameters of noise sources in the further designing stage will constitute input data for selecting fans and establishing the necessary effectiveness of acoustic mufflers.

Results of such calculations concerning the emission of noise into the environment, for C11 station, have been presented in Figure 1. Calculations were made for the maximum noise level inside the intake/exhaust structure (65 dB) and the maximum level of acoustic power for the other local air exhausts (70 dB). 55 dB noise contour line does not go beyond the ul. Świętokrzyska roadway, whereas the noise level within the residential developments zone is lower than 45 dB, thus admissibility conditions are fulfilled. The noise level outside ensures that the requirements for premises inside the neighbouring residential buildings, as defined by the Polish PN-87/B-02151/02 standardare fulfilled as well.

In order to limit the noise emitted outside, all Metro fan houses shall be equipped with equipment of appropriate parameters and with acoustic mufflers. On…usuniete….. the walls and ceilings, in both the main fan house of the C11 station, as well as in chambers, channels and ventilation shafts between the tunnel and the air intake and exhaust shaft, sound-absorbing lining will be applied. The lining shall be made of 100-mm mineral wool covered with glass veil and perforated sheet metal (30% of perforation). Such a silencing system is also to limit the noise of passing Metro trains, which may be emitted outside the tunnel by ventilation ducts through the air intake and exhaust shaft. If necessary, additional elements of protection against the noise emitted by passing Metro trains shall be applied.

Fig. 1. C-11 station, noise emission into the environment