分类： Building Accoustics

大多数工业活动都会产生噪音，对环境及其工人有害。为了最大限度地减少这种影响，政府、协会和公司制定了法规、标准和规范来设定工厂内允许的噪音。在很多情况下，规划阶段中，工厂业主和项目管理层希望确保噪音水平是可以接受的。由于工厂尚未建成，可以做的是创建噪声模型来模拟工厂，以便预测噪声水平。在本文中，我们将探讨如何做到这一点。

我们首先要知道的是工厂内部的噪声源会发出多少噪声。噪声源通常用两种方式描述：声功率级（Lw 或 SWL）和一定距离内的声压级（Lp 或 SPL），最常见的是 1 m 距离内的声压级（Lp 或 SPL）。有多种方法可以获取某些噪声源的信息——首先，如果选择了设备类型和型号，设备制造商通常会在其数据表中报告噪音水平。然而，大多数噪声预测通常并非如此，因为噪声研究通常是在指定设备供应商之前完成的。因此，预测噪声排放的第二种方法是遵循研究人员开发的经验公式。您可以在一些教科书、期刊和论文中找到此类公式。对于旋转部件，您需要其额定功率和转速才能估算噪声排放。

例如，在3000-3600rpm的转速范围内，驱动电机功率在75kW以上的泵的噪声水平可以使用以下公式进行预测：

假设水泵转速为3000rpm、100kW，根据公式可估算出距水泵1m处的噪声级为92dB。假设噪声源可以视为地面上的点源（半球传播），则泵的声功率级可以使用以下公式计算：

其中 r 是从源到接收器的距离。

在这种情况下，预测的 Lw 将为 100 dB。

第三，也可以选择对类似设备进行噪声测量，以确定新设备的噪声水平。另一种选择是，在某些国家/地区，某些设备有噪音排放限制，如果该限制适用于您的项目，您可以使用该限制。

获得所有噪声源的 Lw 后，我们要计算接收器处的噪声水平（Lp）。可以遵循一些标准来计算此值。其中很少有 ISO 9613-2、NORD 2000、CNOSSOS EU 等。大多数标准考虑了一些计算因素，例如距离、大气吸收、地面反射、屏蔽效应（障碍物和障碍物）以及其他因素，例如植被、工业场地等的体积吸收。大多数顾问和项目都需要SoundPLAN 等软件进行此计算。

根据项目的不同，有几种类型的噪声限制需要确保合规。最常见的是环境噪声限值、噪声暴露限值、区域噪声限值和绝对噪声限值。此外，还对紧急情况下的噪音水平进行了建模，以便该信息可用于安全和 PAGA（公共广播和一般警报）研究。

环境噪声限值通常根据工厂对工厂边界以及工厂附近的住宅和学校等最近的敏感接收器的贡献来计算。如何获取该信息取决于适用于厂区的法规。例如，在印度尼西亚，住宅区的噪音限值为 Lsm 55 dBA，工业区的噪音限值为 Lsm 70 dBA。 Lsm 与 Ldn 类似，但夜间噪声级附加值为 5 dB，而不是大多数其他国家（尤其是欧洲国家）使用的 10 dB 附加值。为确保符合本规定，围栏处的噪声水平应低于 Lsm 70 dBA，假设附近有住宅区，则该场地的贡献应低于 55 dBA。还建议测量敏感接收器处的现有噪声水平，以使研究更贴近实际情况。

噪声暴露限值是指工人在工作期间受到噪声的最大暴露量。在印度尼西亚，8 小时工作噪音暴露限值为 85 分贝。要更改工作时间，使用 3 dB 汇率。例如，如果工厂的噪音水平为88分贝，那么工人只能在那里工作4小时，如果是91分贝，那么时间限制为2小时，依此类推。要延长在嘈杂区域的工作时间，可以选择通过减少源头的噪音排放或传输过程中的噪音控制（例如使用屏障）来实际降低噪音水平，或者使用听力保护装置（HPD）来降低噪音水平。耳塞、耳罩等工人。使用 HPD 后工人的噪声暴露可使用以下公式计算：

其中 NRR 是 HPD 的降噪等级（以 dB 为单位）。

不同的区域可能有不同的噪声水平限制，因此区域噪声限制很有用。例如，在无人机械室中，噪声水平可能很高，例如 110 dBA。然而，在现场办公室内部，允许的噪音水平要低得多，例如 50 dBA。应计算该噪声水平以确保符合噪声限值。不同的公司可能对此有不同的限制，以确保员工的健康和生产力。如果该区域位于室内且噪声源位于室外，则可以使用 ISO 12354-3 等标准来估计内部噪声水平。

绝对噪声限值是工厂允许的最高噪声水平，任何时候都不得超过，包括紧急情况。在大多数情况下，脉冲声的绝对噪声限值为 140 dBA。为了确保符合此要求，应计算潜在的高水平噪声，例如安全阀。

紧急情况下，会启动与正常情况不同的噪声源，如火炬、排污阀、消防泵等设备。在这种情况下，工厂内的工人必须能够听到警报和公共广播系统的声音。通常，PAGA 系统的 SPL 目标应比噪声水平高 10 dB 以上。因此，应了解各区域紧急情况下的噪声水平。

Most industrial activities create noise that can be harmful to the environment as well as to their workers. To minimize this effect, governments, associations, and companies have created regulations, standards, and codes to set the allowable noise both inside the sites, that can be harmful to the workers, as well as to the environment. In a lot of cases, during the planning phase, the plant owner and project management want to be sure that the noise levels are acceptable. Since the plant is not built yet, what can be done is creating a noise model to simulate the plant, so that the noise levels can be predicted. In this article, we will explore how we can do so.

The first thing we must know is how much noise does the noise sources inside of the plant will emit. The noise source is usually described in two ways which is Sound Power Level (Lw or SWL), and Sound Pressure Level (Lp or SPL) in certain distance, most commonly Lp in 1 m distance. There are multiple ways to get this information for certain noise sources. First, if the equipment type and model have been chosen, the equipment manufacturer will normally report the noise level in their datasheet. However, this is not usually the case with most of noise predictions since the noise study is normally done before the equipment suppliers are appointed. So, the second way to be able to predict the noise emission is by following empirical formulas that are developed by researchers. You can find such formulas in some textbooks, journals, and papers. For rotating parts, you will need its rated power and rotational speed to be able to estimate the noise emission. 

For example, in the speed range of 3000-3600 rpm, the noise level of a pump with drive motor power above 75 kW can be predicted using the following equation:

Suppose a pump with rotational speed of 3000 rpm and 100 kW, according to the formula, it can be estimated that the noise level at 1 m from the pump would be 92 dB. And suppose the noise source can be considered as point source on the ground (hemisphere propagation), the sound power level of the pump can be calculated using the following formula:

Where r is the distance from source to receiver

And in this case, the predicted Lw would be 100 dB.

Thirds, noise measurement to a similar equipment can also be an option to be able to determine the noise level of the new equipment. Another option, in some countries, there are noise emission limit for certain equipment, you can use that limit if it is applicable for your project.

After the Lw of all noise sources is obtained, we want to calculate the noise levels (the Lp) at the receivers. There are some standards which procedure can be followed to calculate this. Few of which are ISO 9613-2, NORD 2000, CNOSSOS EU, and many others. Most of the standards consider some factors to the calculation such as distance, atmospheric absorption, ground reflection, screening effect (from barriers and obstacles) and other factors such as volume absorption from vegetation, industrial site, etc. Most consultants and projects will require a software such as SoundPLAN to do this calculation.

Depending the project, there are few types of noise limit which compliance will need to be ensured. The most common ones are environmental noise limit, noise exposure limit, area noise limit and absolute noise limit. Besides, the noise level during emergency is also modelled so that the information can be used for safety and PAGA (Public Address and General Alarm) study.

Environmental noise limit is usually calculated for the plant’s contribution to the plant’s boundary as well as to the nearest sensitive receiver such as residential and school near the plant. How this is accessed depends on the regulation applicable on the plant area. In Indonesia for example, the noise limit for residential area is Lsm 55 dBA and industrial area is Lsm 70 dBA. Lsm is a measure like Ldn, but the night noise level addition is 5 dB instead of the 10 dB addition that most other countries, especially Europeans use. To ensure compliance with this regulation, the noise level at fence should be less than Lsm 70 dBA, and suppose there is a residential area nearby, the contribution from the site should be less than 55 dBA. It is also advisable to measure the existing noise level at the sensitive receivers to make the study more relevant to the situation. 

Noise exposure limit is the maximum exposure to noise that the workers get during their working period. In Indonesia, the noise exposure limit is 85 dBA for 8 working hours. To change the working hours, 3 dB exchange rate is used. For example, if the noise level in the plant is 88 dBA, then the workers can only work there for 4 hours, if it is 91 dBA, then the time limit is 2 hours, and so on. To extend the working hours on a noisy area, the options are to actually reduce the noise level by reducing the noise emission from the source or noise control at transmission (for example using barrier), or by usage of Hearing Protection Device (HPD) for the workers such as ear plugs and ear muffs. The noise exposure of workers after usage of HPD can be calculated using the following formula:

Where NRR is the noise reduction rating of the HPD in dB.

Different area might have different noise level limits, and therefore area noise limits are useful. For example, in an unmanned mechanical room, the noise level can be high, for instance 110 dBA. However, inside of the site office, the allowable noise level is much lower, for example 50 dBA. This noise level shall be calculated to ensure compliance with the noise limit. Different companies might have different limits for this to ensure their employees’ health and productivity. If the area is indoor and the noise source is outdoor, then the interior noise level can be estimated using standards such as ISO 12354-3. 

The absolute noise limit is the highest noise level allowable at the plant, and shall not be exceeded at any times, including emergency. In most cases, the absolute noise limit for impulsive sound is 140 dBA. To ensure compliance with this requirement, potential high-level noise shall be calculated, for example safety valves.

During emergency, different noise sources than normal situation will be activated, such as flare, blowdown valves, fire pumps, and other equipment. In such cases, the sound from the alarm and Public Address system must be able to be heard by the workers inside of the plant. Normally the target for the SPL from the PAGA system should be higher than 10 dB above the noise level. Therefore, the noise level during emergency in each area should be well-known. 

Most industrial activities create noise that can be harmful to the environment as well as to their workers. To minimize this effect, governments, associations, and companies have created regulations, standards, and codes to set the allowable noise both inside the sites, that can be harmful to the workers, as well as to the environment. In a lot of cases, during the planning phase, the plant owner and project management want to be sure that the noise levels are acceptable. Since the plant is not built yet, what can be done is creating a noise model to simulate the plant, so that the noise levels can be predicted. In this article, we will explore how we can do so.

The first thing we must know is how much noise does the noise sources inside of the plant will emit. The noise source is usually described in two ways which is Sound Power Level (Lw or SWL), and Sound Pressure Level (Lp or SPL) in certain distance, most commonly Lp in 1 m distance. There are multiple ways to get this information for certain noise sources. First, if the equipment type and model have been chosen, the equipment manufacturer will normally report the noise level in their datasheet. However, this is not usually the case with most of noise predictions since the noise study is normally done before the equipment suppliers are appointed. So, the second way to be able to predict the noise emission is by following empirical formulas that are developed by researchers. You can find such formulas in some textbooks, journals, and papers. For rotating parts, you will need its rated power and rotational speed to be able to estimate the noise emission. 

For example, in the speed range of 3000-3600 rpm, the noise level of a pump with drive motor power above 75 kW can be predicted using the following equation:

Suppose a pump with rotational speed of 3000 rpm and 100 kW, according to the formula, it can be estimated that the noise level at 1 m from the pump would be 92 dB. And suppose the noise source can be considered as point source on the ground (hemisphere propagation), the sound power level of the pump can be calculated using the following formula:

Where r is the distance from source to receiver

And in this case, the predicted Lw would be 100 dB.

Thirds, noise measurement to a similar equipment can also be an option to be able to determine the noise level of the new equipment. Another option, in some countries, there are noise emission limit for certain equipment, you can use that limit if it is applicable for your project.

After the Lw of all noise sources is obtained, we want to calculate the noise levels (the Lp) at the receivers. There are some standards which procedure can be followed to calculate this. Few of which are ISO 9613-2, NORD 2000, CNOSSOS EU, and many others. Most of the standards consider some factors to the calculation such as distance, atmospheric absorption, ground reflection, screening effect (from barriers and obstacles) and other factors such as volume absorption from vegetation, industrial site, etc. Most consultants and projects will require a software such as SoundPLAN to do this calculation.

Depending the project, there are few types of noise limit which compliance will need to be ensured. The most common ones are environmental noise limit, noise exposure limit, area noise limit and absolute noise limit. Besides, the noise level during emergency is also modelled so that the information can be used for safety and PAGA (Public Address and General Alarm) study.

Environmental noise limit is usually calculated for the plant’s contribution to the plant’s boundary as well as to the nearest sensitive receiver such as residential and school near the plant. How this is accessed depends on the regulation applicable on the plant area. In Indonesia for example, the noise limit for residential area is Lsm 55 dBA and industrial area is Lsm 70 dBA. Lsm is a measure like Ldn, but the night noise level addition is 5 dB instead of the 10 dB addition that most other countries, especially Europeans use. To ensure compliance with this regulation, the noise level at fence should be less than Lsm 70 dBA, and suppose there is a residential area nearby, the contribution from the site should be less than 55 dBA. It is also advisable to measure the existing noise level at the sensitive receivers to make the study more relevant to the situation. 

Noise exposure limit is the maximum exposure to noise that the workers get during their working period. In Indonesia, the noise exposure limit is 85 dBA for 8 working hours. To change the working hours, 3 dB exchange rate is used. For example, if the noise level in the plant is 88 dBA, then the workers can only work there for 4 hours, if it is 91 dBA, then the time limit is 2 hours, and so on. To extend the working hours on a noisy area, the options are to actually reduce the noise level by reducing the noise emission from the source or noise control at transmission (for example using barrier), or by usage of Hearing Protection Device (HPD) for the workers such as ear plugs and ear muffs. The noise exposure of workers after usage of HPD can be calculated using the following formula:

Where NRR is the noise reduction rating of the HPD in dB.

Different area might have different noise level limits, and therefore area noise limits are useful. For example, in an unmanned mechanical room, the noise level can be high, for instance 110 dBA. However, inside of the site office, the allowable noise level is much lower, for example 50 dBA. This noise level shall be calculated to ensure compliance with the noise limit. Different companies might have different limits for this to ensure their employees’ health and productivity. If the area is indoor and the noise source is outdoor, then the interior noise level can be estimated using standards such as ISO 12354-3. 

The absolute noise limit is the highest noise level allowable at the plant, and shall not be exceeded at any times, including emergency. In most cases, the absolute noise limit for impulsive sound is 140 dBA. To ensure compliance with this requirement, potential high-level noise shall be calculated, for example safety valves.

During emergency, different noise sources than normal situation will be activated, such as flare, blowdown valves, fire pumps, and other equipment. In such cases, the sound from the alarm and Public Address system must be able to be heard by the workers inside of the plant. Normally the target for the SPL from the PAGA system should be higher than 10 dB above the noise level. Therefore, the noise level during emergency in each area should be well-known. 

Most industrial activities create noise that can be harmful to the environment as well as to their workers. To minimize this effect, governments, associations, and companies have created regulations, standards, and codes to set the allowable noise both inside the sites, that can be harmful to the workers, as well as to the environment. In a lot of cases, during the planning phase, the plant owner and project management want to be sure that the noise levels are acceptable. Since the plant is not built yet, what can be done is creating a noise model to simulate the plant, so that the noise levels can be predicted. In this article, we will explore how we can do so.

The first thing we must know is how much noise does the noise sources inside of the plant will emit. The noise source is usually described in two ways which is Sound Power Level (Lw or SWL), and Sound Pressure Level (Lp or SPL) in certain distance, most commonly Lp in 1 m distance. There are multiple ways to get this information for certain noise sources. First, if the equipment type and model have been chosen, the equipment manufacturer will normally report the noise level in their datasheet. However, this is not usually the case with most of noise predictions since the noise study is normally done before the equipment suppliers are appointed. So, the second way to be able to predict the noise emission is by following empirical formulas that are developed by researchers. You can find such formulas in some textbooks, journals, and papers. For rotating parts, you will need its rated power and rotational speed to be able to estimate the noise emission. 

For example, in the speed range of 3000-3600 rpm, the noise level of a pump with drive motor power above 75 kW can be predicted using the following equation:

Suppose a pump with rotational speed of 3000 rpm and 100 kW, according to the formula, it can be estimated that the noise level at 1 m from the pump would be 92 dB. And suppose the noise source can be considered as point source on the ground (hemisphere propagation), the sound power level of the pump can be calculated using the following formula:

Where r is the distance from source to receiver

And in this case, the predicted Lw would be 100 dB.

Thirds, noise measurement to a similar equipment can also be an option to be able to determine the noise level of the new equipment. Another option, in some countries, there are noise emission limit for certain equipment, you can use that limit if it is applicable for your project.

After the Lw of all noise sources is obtained, we want to calculate the noise levels (the Lp) at the receivers. There are some standards which procedure can be followed to calculate this. Few of which are ISO 9613-2, NORD 2000, CNOSSOS EU, and many others. Most of the standards consider some factors to the calculation such as distance, atmospheric absorption, ground reflection, screening effect (from barriers and obstacles) and other factors such as volume absorption from vegetation, industrial site, etc. Most consultants and projects will require a software such as SoundPLAN to do this calculation.

Depending the project, there are few types of noise limit which compliance will need to be ensured. The most common ones are environmental noise limit, noise exposure limit, area noise limit and absolute noise limit. Besides, the noise level during emergency is also modelled so that the information can be used for safety and PAGA (Public Address and General Alarm) study.

Environmental noise limit is usually calculated for the plant’s contribution to the plant’s boundary as well as to the nearest sensitive receiver such as residential and school near the plant. How this is accessed depends on the regulation applicable on the plant area. In Indonesia for example, the noise limit for residential area is Lsm 55 dBA and industrial area is Lsm 70 dBA. Lsm is a measure like Ldn, but the night noise level addition is 5 dB instead of the 10 dB addition that most other countries, especially Europeans use. To ensure compliance with this regulation, the noise level at fence should be less than Lsm 70 dBA, and suppose there is a residential area nearby, the contribution from the site should be less than 55 dBA. It is also advisable to measure the existing noise level at the sensitive receivers to make the study more relevant to the situation. 

Noise exposure limit is the maximum exposure to noise that the workers get during their working period. In Indonesia, the noise exposure limit is 85 dBA for 8 working hours. To change the working hours, 3 dB exchange rate is used. For example, if the noise level in the plant is 88 dBA, then the workers can only work there for 4 hours, if it is 91 dBA, then the time limit is 2 hours, and so on. To extend the working hours on a noisy area, the options are to actually reduce the noise level by reducing the noise emission from the source or noise control at transmission (for example using barrier), or by usage of Hearing Protection Device (HPD) for the workers such as ear plugs and ear muffs. The noise exposure of workers after usage of HPD can be calculated using the following formula:

Where NRR is the noise reduction rating of the HPD in dB.

Different area might have different noise level limits, and therefore area noise limits are useful. For example, in an unmanned mechanical room, the noise level can be high, for instance 110 dBA. However, inside of the site office, the allowable noise level is much lower, for example 50 dBA. This noise level shall be calculated to ensure compliance with the noise limit. Different companies might have different limits for this to ensure their employees’ health and productivity. If the area is indoor and the noise source is outdoor, then the interior noise level can be estimated using standards such as ISO 12354-3. 

The absolute noise limit is the highest noise level allowable at the plant, and shall not be exceeded at any times, including emergency. In most cases, the absolute noise limit for impulsive sound is 140 dBA. To ensure compliance with this requirement, potential high-level noise shall be calculated, for example safety valves.

During emergency, different noise sources than normal situation will be activated, such as flare, blowdown valves, fire pumps, and other equipment. In such cases, the sound from the alarm and Public Address system must be able to be heard by the workers inside of the plant. Normally the target for the SPL from the PAGA system should be higher than 10 dB above the noise level. Therefore, the noise level during emergency in each area should be well-known.