Printer Friendly

HAZOP study and risk assessment in three-phase separator oil and gas exploration farm--East Java, Indonesia.


Security and safety is something that is important and a major state in the world of work, especially when jobs are executed at high risk for the safety of workers and the environment. Danger (hazard) which can lead to endangerment of safety of life and the environment can occur on things unpredictable even underestimated. According to the OHSAS 18001: 2007, the danger (hazard) is all sources, situation or activity that has the potential to cause injury (accident) and occupational diseases. Therefore it is necessary to audit the work environment in order to predict the hazard that can occur and the subsequent risk management planning (risk management) for the handling of such hazards. Dhillon, B.S., [2].

PT. Joint Operating Body PERTAMINA--Petrochina is a joint venture entity of PT. Pertamina (Persero) is a State-Owned Enterprises (SOEs), Indonesia with PT. Petrochina- Indonesia, Ltd. PT. JOB (Joint Operating Body) Pertamina-Petrochina including upstream company in terms of oil and gas exploration (oil and gas) with drilling activity, separation of crude oil and distribution for advanced process to partner companies PT. Joint Operating Body Pertamina--Petrochina. In the implementation of these activities, PT. Joint Operating Body Pertamina-Petrochina manages materials classified as hazardous. Danger may occur due to the nature and content of various chemicals contained in crude oil which is the result of the drilling, one of the elements is H2S, is a substance that is most prone to fire and gas leakage H2S as toxic gas. Skrtic, Lana [20].

The potential hazard could cause accidents; the purpose of the research guaranteed for the safety of the workers with the most severe consequence is death. Potential work accidents are caused by the toxic properties of H2S gas and crude oil properties itself flammable. Potential accidents that can involve citizens more widely around the plant. That is because the H2S gas is carried by the wind and the volume of crude oil very much, quite capable of burning plant area of PT. JOB Pertamina-Petrochina and the surrounding environment. Danger may occur due to system failure or hardware security and control system at the plant. Small failures that occurred could have a domino effect if there is no emergency to evaluate and improve the system failure. From such exposure, this is the background for such research activities (HAZOP), Robert W. Johnson, [17]. And the assessment of risk management (Risk Management) for the protection of potential hazards and the preparation of emergency response plan (ERP) for the implementation of mitigation on PT. JOB Pertamina-Petrochina. With these evaluations can then unknown source of the problems of potential hazards that can then be built safeguards to reduce the level of risk and accidents that will occur in the PV-9900 unit. Musyafa, A., and Zulfiana, E., [11].

2. Methodology:

2.1 Plant Separator:

Separator is equipment that is commonly used in industry. The function of separator is to separate certain liquids with other liquids with different density or boiling point or separating a mixture of materials in order to obtain its constituent materials by breaking down the materials that have different phases. The working principle of this equipment separates the gas and liquid are first performed by crashing production drilling results into the inlet diverter that material outlining the system liquid and gas from the well. Furthermore, legally physics of gas will rise to the top position and liquid separator will drop. Temilade Ladokun and Farhad N., [21]. Liquid separation technique using the difference principle density, while the density of water is heavier bring down to the separator and crude oil that has a density lighter water rises to the surface. The bottom of the separator has two rooms separated by a weir. Weir will keep the water would not move to another room, while the oil is above the water will pass through the weir heights and flows into the second chamber so that the results of the threephase separator is processed is the separation of gas, oil and water. Three substances material separation from the drilling results will be forwarded to the advanced process. For products forwarded to scrubber and flare gas, oil products to be forwarded to a stripper, and to be forwarded to the water gas water boot. The following threephase separator shown specification PV-9900 is shown in Table 1. [5].

2.2 HAZOP Study:

Hazard and Operability Study (HAZOP) is a structured engineering study to evaluate and assess the risk management system. HAZOP study is useful as a technique for identifying a potential danger in the process. Musyafa. A, et al. [12]. HAZOP is a theory that assumes that risk is caused by deviation of the design or operating purposes. Identification of deviation of design or operating purposes is facilitated by using the 'guidewords' as systematic list of perspective deviation. This approach is unique from HAZOP methodologies that help stimulate the imagination while exploring a potential deviation. HAZOP is suitable to be deployed to assess the hazards in facilities, equipment, and processes. HAZOP able to assess the system from a variety of perspectives. Fletcher, Lyn E., [4].

> Design: The ability to assess the system design to achieve the desired specifications and safety standards.

> Identify weaknesses in the system: the physical and operational environment, assess the environment to ensure the system in the right situation.

> Procedural and operational control system: estimating control engineering (automation), sequensial operation, control procedures (human interaction), etc. And assess the various operational modes--start-up, standby, normal operation, steady and unsteady states, normal shutdown, emergency shutdown, etc.

2.3 Risk:

Risk is the likelihood combination possibilities and consequences that occur according to the following equation 2.1.

Risk = (Consequence) x (Likelihood) (1)

MTTF is the mean value of the instrument have failed in a certain period of time. Every day plant- III sulfuric acid fully operational within 24 hours. Likelihood is calculated by equation (2).

Likelihood = (1/MTTF) x 43800 jam (2)

By the standards of the Australian / New Zealand (AS / NZS 4360: 2004), the consequences can be determined based on the level of a few tables consequences criteria as shown in Table 2. Ebeling, Charles E., (1997).

Frequency is evaluated based on the number of the occurrence of hazards. Frequency can also be evaluated based on historical data or from the same component failures that have occurred on the component failure rate based on the data. By the standards of the Australian / New Zealand (AS / NZS 4360: 2004), the level of likelihood can be determined based on criteria such as shown in Table 3.

By Equation (2.1), is the result of multiplying the value of risk likelihood and consequences, so that subsequently obtained a risk matrix criteria as shown in Table 4. Montgomery, Douglas C. [9].

2.4 Risk Management:

Risk management is part of the process management phases. The purpose of risk management to minimize losses and increase the chance or opportunity. Basically, risk management is the prevention of the occurrence or accident keugian. Tahapan of the first risk management process is to determine the content that is to be analyzed, which includes data collection strategies, risk management methods, as well as the determination criterion. The next stage risk identification that includes risks that will occur from the hazards are analyzed and how these risks can occur. For the risk analysis stage, estimate the likelihood and consequences, can further known risk criteria based on the result of the combination of likelihood and consequences. The next evaluation of risk, whether the risk is acceptable or not, if not then continued efforts to reduce the risk of handling. In the implementation of these measures, always do the communication and consultation between the members and do monitor and review. Musyafa, A. et al [13].

2.5 Evaluation of Risk Management:

In this discussion outlined evaluation measures for risk management and hazard operability study. The object of research here three phase separator to function as crude oil separator results from drilling wells into three products namely oil, water, and gas. The study began with a literature study on matters related to the separator, among others: risk management and hazard and operability study will be implemented safety standards such as IEC 61508. The next phase maintenance collect data, process data and other supporting data. Phase berkut perform data processing. seek control charts, tables mebuat cause and consequences, likelihood tables, as well as the risk matrix table. Data processing analysis and tabulated hazard and operability (HAZOP). HAZOP validated against a table that has been built. If the results are not valid it must be repeated on a data processing step. At the stage of data processing as well prepared emergency response plan (ERP). Assumed if the one-step preparation of risk management is further assumed to be an explosion at the plant Separator PV9900. Then steps need to be prepared to anticipate these events. Jeerawongsuntorn. et al. [6], Poulose, [16]. The flow chart of research shown in Figure 1.


3.1 Process and Input /Output:

Study points (nodes) that are determined to be investigated is input separator (separator input), vessel (vessel), the output separator (separator output). Data sought further plant that will produce an average value vairabel operation, deviation, likelihood and severity. Maintenance of data sampled over 5 years starting in September 2009--August 2014. The process data is used as study materials sampled during the two months of November 2014--December 2014 next. Based on these data hereafter devised control chart and calculations are discussed and form the basis of creating a table HAZOP. Musyafa, A., and Kristianingsih, L., [11]

3.2 Guideword and Deviation:

In the separator system as a whole made guideword as shown by Table 5.

Based on Table 4.1, it can be observed that the system of three-phase separator guideword PV-9900 consists of; high and low pressure, and temperature, as well as more, less, and as well as to the flow rate. From the guideword then made a table hazard operability study and its recommendations for addressing the threat that is likely to occur. [7].

3.3 Likelihood:

Likelihood value is determined based on the data that is recorded on the maintenance instrument division of PT. JOB PPEJ-Tuban. Likelihood obtained by dividing Operating time for 5 years in hours and Mean Time to Failure (MTTF) in an hour anyway. The MTTF is obtained with an average seek time of a status instrument to undergo restoration, recalibration and damage equipment. Having obtained the likelihood at each node, the next step to formulate any node that is an integral three-phase separator system PV-9900. The following results are calculated based on the likelihood that the data collected from all three phase separator system PV-9900.Adapun Likelihood criteria shown in Table 6.

Further step is to formulate that each node becomes a sub-system of the three-phase separator PV-9900. From Table 4.2, it can be observed that the likelihood for the entire system has a dominant likelihood criteria is at the D criteria, the criteria for the position of E, D, and C. Thus the emergence of these systems have a range of system failure with rare criteria--moderate. This shows that the system cukupsering failure. However, the level of its appearance is still within reasonable limits and still be tolerated.

3.4 Consequences:

Consequences analysis was conducted to determine the approximate severity (severity) and possible effects caused by the deviation of the average operating variables. From the data created process control chart that shows some degree of control achieved by the data limit. Based on the level of control limit calculation is then adjusted to a category consequences.

Formulation consequences on the overall three-phase separator system PV-9900 is done by combining the consequences on each node. On criteria such consequences can be observed that the three-phase separator system PV-9900 has consequences criteria 1 and 3 were nearly balanced. Criteria 1 and 3 indicates that the consequences insignificant and moderate, it indicates that when there is a failure in the separator, it will berakibatkan to the most severe conditions, especially the failure of the system that caused the engine to lose its function and lead to product failure. John N. Dyer, et al. [8].

4 .Result:

4.1 Risk Matrix:

Analysis of risk matrix aims to map the risks that can occur in a system with data sources likelihood and consequences. As shown by Table 8.shown risk matrix.

Risk matrix system is a combination of risk matrix each node. The combined number of risk level of each node to the low risk category amounted to 5, in the category of moderate risk amounted to 3, and in the high risk category amounted to 1, and the risk for the category = 0. If likelihood and consequences on every node coupled the importance of the risk matrix as Reviewed shown by table 8. Of the risk matrix can be observed that the three-phase separator PV-9900 occupies an area of risk in the range of low risk to high risk. High level of risk that may occur in the three-phase separator to be assessed hazard operability study to improve the ability to prevent danger. Silvana.D.Costa. et al. [19].

4.2 Risk Management:

Based on the risk analysis has been done, the explosion is a potential hazard may occur due to excessive pressure. It is due to the input node of the whole separator, and putput separator has a variable pressure that may exceed the threshold value. When an explosion is the most dangerous thing H2S gas leakage which radiate into the surrounding environment. H2S gas can easily be spread quickly because of the presence of wind. Therefore necessary emergency response plan (ERP) when the situation occurs. Here is a map of the spread of H2S according to the wind direction is often the case (of the local weather data) and maps of the center of activity at the center point area (CPA). Shown in Figure 2. Ronny D.N., et al. [18]

4.3 Recommendation:

From the analysis made on and needs to be done to support the safety of workers in the unit CPA: Because of the office side of the south CPA and safe briefing areas (SBA) parts of the south, including areas affected by the distribution of H2S gas when separator exploded then it is recommended that, for these two places are provided mask the same amount or slightly more than the number of workers. Providing and setting up a bus or other transport equipment quickly to relocate workers who gathered in the southern part of the SBA, this is due SBA southern part including areas affected by the distribution of H2S and need immediate redeployment of workers who had gathered at the site

4.4 Emergency Response Plan (ERP):

Beradasarkan analysis, when an explosion is a potential hazard that occurs in the three-phase separator PV-9900. The condition is caused by a high pressure separator which in turn drive a wedge components. If this was not well anticipated. Then the explosions may occur and could potentially lead to a domino effect that occurs following an explosion. There are several countermeasures if it happens that early prevention and advanced countermeasures.

4.5 Early Countermeasures:

In the initial response, there are several actions that should be performed by the operator, when the threephase separator PV-9900 having a blast and the subsequent alarm namely:

* Do not Panic.

* Stop all activity and extinguish all sources of energy.

* Turn off the car and get off when were on the vehicle.

* Please find and wear masks to minimize the impact of inhalation of H2S gas.

* A quick walk do not run toward safe briefing area (SBA) north for all workers in the control room

* and towards safe briefing area (SBA) for workers in the southern part of the southern part of the

* CPA's office.

* Please pass routes that have been provided as in Figure 4.2.

* Ignoring other workers who had fallen or fainted when the precarious state and focus towards safe

* briefing areas (SBA).

* Counting and ascertain the number and personal data of workers gathered at the safe briefing area (SBA).

In Figure 3. are recommended evacuation routes to reach safe briefing area (SBA) nearby. In the eastern region are encouraged to follow the purple route to the nearest SBA SBA is south and west to the area are encouraged to follow these SBA blue towards the north. At the service is set up so that workers and employees can reach the nearest SBA

4.6 Advanced Countermeasures:

In penangulangan was undertaken after or simultaneously with the initial response to the steps as follows:

* Paramedics immediately combed the field with first aid equipment on the accident (P3K) which has provided with an ambulance ride to find workers who have gathered in the briefing safe area (SBA) and evacuate to safe briefing area (SBA).

* field commander rushed to muster points CPA, wear protective gear and coordinate with emergency response team (ERT) and conducted an analysis of the problems that occur and determine the equipment and personnel necessary to control the situation.

* deputy field commander soon master menu point CPA, wear protective gear and coordinate with field commander. As well as done some preliminary investigations on the problem and take appropriate action in addressing the problems.

* Tim emergency response team (ERT) to the muster point and wear protective gear, and assist deputy field commanders to investigate problems, coordinate and execute the instructions of deputy field commander.


Based on research that has been done can be concluded as follows: Assessment hazard operability study showed that of the data maintenance and process data that has been processed obtained HAZOP which mangacu on guideword and can further assessed risk in the low category = 5, the risk in the category of moderate = 3, in the category of high risk = 1, and the risk for the category Catastropic = 0. to improve system security needs to be improved intensity of inspection and maintenance as it has made recommendations HAZOP and implement emergency response plan, so that the security and safety of workers and employees can be guaranteed when there is a failure as a result of PV-9900 separator explosion.


[1.] Australian Standard/New Zealand Standard 4360, 1999. "Risk Management", Australian Standard, 1998

[2.] Dhillon, B.S., 2005. Reliability, Quality, and Safety for Engineers. London : CRC Press

[3.] Ebeling, Charles E.,1997. "An Introduction to Realibility and Maintainability Engineering", The McGrawHill Companies, Inc, Singapore.

[4.] Fletcher, Lyn E., 1998."Potential Explosive Hazards from Hydrogen Sulfide Production in Ship Ballast and Sewag Tanks", Aeronautical and Maritime Research Laboratory, Australia.

[5.] Gruhn, Paul, Harry Cheddie, 2005. Safety Instrumented System Verivication: Practical Probabilitic Calculations. United State of America: ISA.

[6.] Jeerawongsuntorn, et al., 2011. Integration of Safety Instrumented System with Automated HAZOP Analysis: An application for continuous biodiesel production. Science Direct., pp: 412-419.

[7.] Jin Jianghong, et al., 2015. Quantitative assessment of probability of failing safely for safety instrumented system using reliability block diagram method. Annals of Nucler Energy, 77: 30-34.

[8.] John N. Dyer, Anay P. Raibagkar, Massimiliano Kolbe, dan Ernesto Salzano, 2012. "Blast Damage Considerations for Horizontal Pressure Vessel and Potential for Domino Effects", The Italian Association of Chemical Engineering, Italy.

[9.] Montgomery, Douglas C., 2009. "Introduction to statistical Quality Control 6th Edition", United States of America.

[10.] Musyafa, A. And L. Kristianingsih, 2013. "Risk Management and Safety System Assesment from Power Plant Steam Boiler in Power Systems Unit 5, Paiton Indonesia", Australian Journal of Basic and Applied Sciences, Australia.

[11.] Musyafa, A. And Zulfiana, Erna, 2013. "Risk Management and Hazard and Operability Study on Steam Turbine Power Plant Unit 5 in The Power Generation Paiton, East Java-Indonesia", Australian Journal of Basic and Applied Sciences, Australia.

[12.] Musyafa, A, et al., 2015. Hazad And Operability Study and Analysis of Safety Integrity Level Case Study: Ammonia Refrigerant Compressor at Petrocemical Plant, AENSI Journals, Advances in Natural and Applied Sciences, 9(8): 36-42.

[13.] Musyafa, A. et al., 2014. Reliability and Maintainability Assessment of the Steam Turbine Instrumentation System for optimization Operational Availability System at Fertilizer Plant, Australian Journal of Basic and Applied Sciences, 8(13): 132-139.

[14.] Musyafa, A. et al., 2015. Evaluation of the Reliability and Prediction Maintenance on the Air Compressor., Australian Journal of Basic and Applied Sciences, 9(11): 853-862.

[15.] System in Ammonia Plant PT. Petrokimia Gresik

[16.] Poulose, Smera Maria, G. dan Madhu, 2012. "Hazop Study for Process Plants: A Generalized Approach", International Journal of Emerging Technology and Advanced Engineering.

[17.] Robert, W. Johnson, 2010. Beyond-compliance uses of HAZOP/LOPA studies. Science Direct., pp: 727733.

[18.] Ronny, D. Noriyati, et al., 2014." Reliability Assessment of Cooling Pump For Parts Inventory Planning in Power Plant System, Paiton-Indonesia". Australian Journal of Basic and Applied Sciences, 8(13): 140-146, AENSI Journals Australian Journal of Basic and Applied Sciences ISSN:1991-8178. Journal home page:

[19.] Silvana, D. Costa. et al., 2015. Evaluation Safety Integrity Level Using Layer of Protection Analysis in Recycle Gas First Stage Cycle Compressor at PT. Pertamina Persero., Australian Journal of Basic and Applied Science.

[20.] Skrtic, Lana, 2006. "Hydrogen Sulfide, Oil and Gas, and People's Health", Energy and Resources Group University of California, Berkeley.

[21.] Temilade Ladokun, Farhad Nabhani, 2010. "Accidents in Pressure Vessels: Hazard Awareness", World Congress on Engineering, U.K.

(1) Ali Musyafa, (2) Rozzy Kresna, A.A, (3) Hendra Cordova, (4) Ronny D.Noriyati,

(1) Ass. Professor, Department of Engineering Physics, Faculty of Industrial Enginering, Institut Teknoiogi Sepuiuh Nopember, Box. ITS Surabaya, Surabaya, Indonesia.

(2) Reseacher, Department of Engineering Physics, Faculty of Industrial Enginering, Institut Teknoiogi Sepuiuh Nopember, Box. ITS Surabaya, Surabaya, Indonesia.

(3) Lecturer, Department of Engineering Physics, Faculty of Industrial Enginering, Institut Teknoiogi Sepuiuh Nopember, Box. ITS Surabaya, Surabaya, Indonesia.

(4) Ass. Professor, Department of Engineering Physics, Faculty of Industrial Enginering, Institut Teknoiogi Sepuiuh Nopember, Box. ITS Surabaya, Surabaya, Indonesia.

Received 18 January 2017; Accepted 22 February 2017; Available online 26 March 2017

Address For Correspondence:

Ali Musyafa, Department of Engineering Physics, Faculty of Industrial Enginering. Institut TEeknologi Sepuluh Nopember, Surabaya, Indonesia.

Caption: Fig. 1: Flowchart of the Research

Caption: Fig. 2: Map of the center of activity (CPA) and in the spread of H2S

Caption: Fig. 3: Evacuation route to the safe briefing area (SBA)
Table 1: Specifications Three-Phase Separator, PV-9900

Tag NumberSpesifikasi

          Size                  144" ID x 30'-0" T/T
          Design Pressure       286 PSIG@250[degrees]F
PV-9900   Operating Pressure    125 PSIG@180[degrees]F
          Corrosion Allowance   0.0125 INS
          Materials             A-516 GR 70
          Capacity              5000 OPD/50000 BWPD / 40 MM

Table 2: Table Consequences, (The Standard Australia / New Zealand
(AS / NZS 4360: 2004)

Level   Guideword       Description

1       Insignificant   The system operates and safe, there was a
                        slight disturbance does not mean

2       Minor           The system continues to operate and secure,
                        interference resulted in a slight decrease in
                        performance or, impaired system performance

3       Moderate        The system can operate, failure may result in
                        the machine loses its main function and / can
                        cause product failure

4       Major           The system cannot operate. Failure can cause a
                        lot of physical damage and system, can cause
                        product failure, and / does not meet regulatory
                        requirements Safety

5       Catastrophic    System operation is not feasible, the severity
                        of which is very high if the failure affects a
                        secure system, in violation of regulations

Table 3: Likelihood base on The Standard Australia/New Zealand (AS/
NZS 4360:2004)

Level   Guide word       Description

A       Almost certain   Risks occurring more than 5 times in 5 years
B       Likely           Risk of more than 4-5 times in 5 years
C       Moderate         Risk of more than 3 or less than 4 in 5 years
D       Unlikely         Risk of 2-3 times in 5 years
E       Rare             Risks rarely, appear/occur less than two
                         times in 5 years

Table 4: Risk Matrix (The Standard Australia/New Zealand (AS/NZS


Likelihood     Insignificant   Minor   Moderate   Major   Catastrophic

                     1           2        3         4          5

A (Almost            H           H        E         E          E
B (Likely)           M           H        H         E          E
C (Moderate)         L           M        H         E          E
D (Unlikely)         L           L        M         H          E
E (Rare)             L           L        M         H          H

Table 5: Guideword Three Phase Separator system PV-9900

No.   Component                      Guideword    Deviation

1.    Pressure Indicator (PI-9910)   High         Higher Pressure
                                     Low          Lower Pressure
2.    Pressure Indicator Control     High         Higher Pressure
3.    Pressure Indicator (PI-9944)   Low          Lower Pressure
4.    Flow Indicator (FI-9941)       More         More Flow
                                     Less         Less Flow
5.    Temperature Indicator          High         Higher Temp.
        (TI-9944)                    Low          Lower Temp.
6.    Pressure Indicator (PI-9932)   As Well As   As Well As Pressure
7.    Pressure Indicator Control     High         Higher Pressure
8.    Pressure Indicator (PI-9944)   Low          Lower Pressure
9.    Flow Indicator (FI-9941)       More         More Flow
                                     Less         Less Flow
10.   Temperature Indicator          High         Higher Temp.
        (TI-9944)                    Low          Lower Temp.
11.   Pressure Indicator (PI-9932)   As Well As   As Well As Pressure

Table 6: Criteria Likelihood entire three-phase separator
system PV-9900

Instrument   MTTF (Jam)   Likelihood   Kriteria Likelihood

SDV-9904     16936        2.59         E
OLT-9934     25416        1,72         E
LIC 9935     19404        2.26         D
PSV-9931     21888        2,001        D
PSV-9932     21888        2,001        D
TT-9939      21888        2,001        D
PCV-9947A    14584        3,003        C
BDV-9961     21888        2,001        D
TT-9969      21888        2,001        D

Table 7: Criteria consequences three-phase separator system PV-9900

No.   Instrumen                               Kriteria Consequences

1.    SDV-9904 (PI-9910)                      1
2.    Temperature Indicator                   3
3.    Oil Level Transmitter                   3
4.    InterfaceLevel Transmitter (ILT-992)    1
5.    Pressure Indicator Control (PIT-9932)   1
6.    Pressure Indicator (PI-9944)            1
7.    Flow Indicator (FI-9941)                3
8.    Temperature Indicator                   3
9.    Pressure Indicator                      1

Table 8: Risk Matrix three-phase separator PV-9900

Likelihood     Consequences

               Insignificant   Minor   Moderate   Major   Catastrophic

               1               2       3          4       5
A (Almost
B (Likely)
C (Moderate)   PV-9900                 PV-9900
D (Unlikely)   PV-9900                 PV-9900
E (Rare)       PV-9900                 PV-9900
COPYRIGHT 2017 American-Eurasian Network for Scientific Information
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2017 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Musyafa, Ali; Kresna, Rozzy; A.A; Cordova, Hendra; Noriyati, Ronny D.
Publication:Advances in Natural and Applied Sciences
Article Type:Report
Geographic Code:9INDO
Date:Mar 1, 2017
Previous Article:Enhancing the dual polarization O-OFDM systems using different effective areas for the optical fiber.
Next Article:Calculating the inverse radial distortion model based on Zhang method.

Terms of use | Privacy policy | Copyright © 2019 Farlex, Inc. | Feedback | For webmasters