**2. Facilities and experimental setup**

The Airliner Cabin Environment Research Lab (ACERL) houses two Boeing mockup cabins, a bleed air simulator, and a half cabin generic room. The details and specifications of each of the four structures are as follows:

### **2.1 Generic aircraft half-cabin mockup model**

This generic model represents a half, twin-aisle, Boeing aircraft cabin. It has dimensions of L × W × H = 2.1 m × 2.1 m × 1.7 m in height (6.4 ft × 6.4 ft ×5.1 ft). The actual built-up room and a generic CAD model for this facility are shown in **Figure 1** [2, 3].

### **2.2 Boeing 767 cabin mockup**

This structure represented a full size and wide body Boeing aircraft cabin mockup that was entirely built and validated at the ACERL. It consisted of 11 rows of seats, along the length of the cabin, with seven seats in the lateral (transverse) direction. The dimensions of the cabin mockup were 9.6 m (31 ft 5 in.) in length and 4.7 m (15 ft 6 in.) wide at the widest spot right above the arm seats area. The mockup cabin seats, the air supply duct, and linear diffusers are original parts from a salvaged Boeing 767 aircraft. Each seat in the cabin was occupied by an inflatable manikin, shown in **Figure 2c**, which was instrumented with a 10 m-long wire heater element to generate approximately 100 W (341 Btu/h) of distributing heat, representing heat gains from a sedentary human being. The supplied air to the cabin mockup was 100% fresh air with no recirculated air. Air temperature was controlled via a chiller and a heater loop as shown in **Figure 2b**. Prior to supplying the outdoor fresh air into the cabin mockup, a set of high-efficiency particulate air (HEPA) filters was installed in series with the supply duct, as shown in **Figure 2a**. Following the HEPA filter, the air was supplied to linear diffusers inside the cabin mockup. Air was exhausted from the bottom of the cabin mockup. The total airflow rate supplied to the cabin was approximately 660 l/s (1400 CFM) of fresh air, thus allowing 8.57 l/s (18 CFM) for every seat of the 77-seats available in the cabin. The

**5**

*Air Quality and Airflow Characteristic Studies for Passenger Aircraft Cabins*

temperature of the air inside the cabin was controlled to 23–25°C which met the recommended design values for inside passenger aircraft cabins. It was important to insure that the air supplied through the two linear diffusers was balanced to maintain airflow uniformity inside the cabin. Also, the duct supplying the two diffusers had a decreasing diameter along the length of the cabin to allow uniform pressure. Although the uniformity of the air exiting the cabin was not a necessity, the exhaust area was uniform along the full length of the cabin and was open into a larger

*Boeing 767 cabin mockup (a) exterior, (b) supply air system and control, and (c) interior of the cabin with* 

Two different sections of actual narrow body Boeing 737 aircraft cabins were used. The first one included three rows of seats with a total number of 18 seats. The seats were equipped with heated cylinders releasing approximately 100 W (341 Btu/h) except one seat that was equipped with a thermal manikin simulating a human body generating 100 W (341 Btu/h), as well. Cabin dimensions are shown in **Figure 3**. The other cabin size was 5.6 m (18.3 ft) in length, 3.6 m (11.8 ft) in width, 2.8 m (9.2 ft) in height and is shown in **Figure 4**. It consisted of five rows with 30 seats in total. All seats were equipped with similar inflatable-heated manikins as was described and used in the Boeing 767 cabin mockup. The airflow and temperature for both cabins were controlled meeting the specifications described for the

To help in identifying contamination sources onboard actual aircraft, HEPA filters were extracted from the air recirculation ducts from actual aircraft and were analyzed using the bleed air simulator shown in **Figure 5**. To simulate oil leakage,

plenum that has negligible pressure gradients.

Boeing 767 cabin mockup described previously.

**2.3 Boeing 737 sectional cabin**

*inflatable manikins in each seat shown [1, 4, 5].*

**Figure 2.**

**2.4 Bleed air simulator**

*DOI: http://dx.doi.org/10.5772/intechopen.87307*

*Air Quality and Airflow Characteristic Studies for Passenger Aircraft Cabins DOI: http://dx.doi.org/10.5772/intechopen.87307*

**Figure 2.**

*Indoor Environment and Health*

stand airflow behavior inside aircraft cabins.

specifications of each of the four structures are as follows:

**2.1 Generic aircraft half-cabin mockup model**

**2. Facilities and experimental setup**

**2.2 Boeing 767 cabin mockup**

In addition to that, the studies presented in this chapter provide important information to help in validating simulations and CFD codes developed to under-

The Airliner Cabin Environment Research Lab (ACERL) houses two Boeing mockup cabins, a bleed air simulator, and a half cabin generic room. The details and

This generic model represents a half, twin-aisle, Boeing aircraft cabin. It has dimensions of L × W × H = 2.1 m × 2.1 m × 1.7 m in height (6.4 ft × 6.4 ft ×5.1 ft). The actual built-up room and a generic CAD model for this facility are shown in **Figure 1** [2, 3].

This structure represented a full size and wide body Boeing aircraft cabin mockup that was entirely built and validated at the ACERL. It consisted of 11 rows of seats, along the length of the cabin, with seven seats in the lateral (transverse) direction. The dimensions of the cabin mockup were 9.6 m (31 ft 5 in.) in length and 4.7 m (15 ft 6 in.) wide at the widest spot right above the arm seats area. The mockup cabin seats, the air supply duct, and linear diffusers are original parts from a salvaged Boeing 767 aircraft. Each seat in the cabin was occupied by an inflatable manikin, shown in **Figure 2c**, which was instrumented with a 10 m-long wire heater element to generate approximately 100 W (341 Btu/h) of distributing heat, representing heat gains from a sedentary human being. The supplied air to the cabin mockup was 100% fresh air with no recirculated air. Air temperature was controlled via a chiller and a heater loop as shown in **Figure 2b**. Prior to supplying the outdoor fresh air into the cabin mockup, a set of high-efficiency particulate air (HEPA) filters was installed in series with the supply duct, as shown in **Figure 2a**. Following the HEPA filter, the air was supplied to linear diffusers inside the cabin mockup. Air was exhausted from the bottom of the cabin mockup. The total airflow rate supplied to the cabin was approximately 660 l/s (1400 CFM) of fresh air, thus allowing 8.57 l/s (18 CFM) for every seat of the 77-seats available in the cabin. The

*Half full scale cabin (a) generic room [2] and (b) generated CAD model [3] (dimensions in mm).*

**4**

**Figure 1.**

*Boeing 767 cabin mockup (a) exterior, (b) supply air system and control, and (c) interior of the cabin with inflatable manikins in each seat shown [1, 4, 5].*

temperature of the air inside the cabin was controlled to 23–25°C which met the recommended design values for inside passenger aircraft cabins. It was important to insure that the air supplied through the two linear diffusers was balanced to maintain airflow uniformity inside the cabin. Also, the duct supplying the two diffusers had a decreasing diameter along the length of the cabin to allow uniform pressure. Although the uniformity of the air exiting the cabin was not a necessity, the exhaust area was uniform along the full length of the cabin and was open into a larger plenum that has negligible pressure gradients.

#### **2.3 Boeing 737 sectional cabin**

Two different sections of actual narrow body Boeing 737 aircraft cabins were used. The first one included three rows of seats with a total number of 18 seats. The seats were equipped with heated cylinders releasing approximately 100 W (341 Btu/h) except one seat that was equipped with a thermal manikin simulating a human body generating 100 W (341 Btu/h), as well. Cabin dimensions are shown in **Figure 3**. The other cabin size was 5.6 m (18.3 ft) in length, 3.6 m (11.8 ft) in width, 2.8 m (9.2 ft) in height and is shown in **Figure 4**. It consisted of five rows with 30 seats in total. All seats were equipped with similar inflatable-heated manikins as was described and used in the Boeing 767 cabin mockup. The airflow and temperature for both cabins were controlled meeting the specifications described for the Boeing 767 cabin mockup described previously.

#### **2.4 Bleed air simulator**

To help in identifying contamination sources onboard actual aircraft, HEPA filters were extracted from the air recirculation ducts from actual aircraft and were analyzed using the bleed air simulator shown in **Figure 5**. To simulate oil leakage,

#### **Figure 3.**

*3-rows B737 cabin side view schematic (dimensions in mm) [6].*

#### **Figure 4.**

*5-rows B737 (a) exterior and (b) interior with inflatable heated manikins [7].*

**Figure 5.** *Bleed air simulator [8].*

a compressor was used with an oil generator forcing oil droplets in the testing duct where the filters were installed. A reciprocating compressor followed by a heated tube was used to create controlled temperature and pressure conditions representative of bleed air from an aircraft engine. Aerosolized lubricating oil was injected into the airflow upstream of the compressor and the particulate characteristics were measured downstream of the heated tube. Gas chromatograph-mass spectrometry (GC/MS) was used in the analysis [9].

Important key factors that can affect the accuracy of the results obtained were the duration of oil existence on the filters, storage conditions and duration of the filters, and oil evaporation [10].

**7**

**Table 1.**

*Air Quality and Airflow Characteristic Studies for Passenger Aircraft Cabins*

The progress of the studies conducted at the ACERL Lab is summarized as shown in **Table 1**. Investigation started with PIV techniques for structures' validation and to help in validating the computational fluid dynamics (CFD) codes development. This included multiple studies such as by [3, 6, 13, 16]. At the same time, literature was conducted to understand and evaluate air quality inside aircraft cabins such as by [11, 12, 14, 18]. In 2006, a new phase of investigation for air quality and airflow was approved by the US Federal Aviation Administration (FAA). The team started their investigation inside the B767 cabin mockup described in Section 2.2 and shown in **Figure 2**. The investigation started with particles dispersion inside the aircraft cabin mockup while working on more literature including air characterization inside aircraft cabins, contamination and viruses monitoring development, and other viruses related literature studies. After obtaining enough initial results,

**CFD PIV Tracer gas Particles Bleed air Others**

Lin et al. [16] Jones [18]

Shehadi et al. [23]

Beneke et al. [28]

Powell et al. [36]

[43]

Korves et al. [29]

Eckels et al. [9], Mann et al. [37]

[10]

[1]

Jones et al. [41], Space et al. [42]

Jones [14]

Jones [24], Loo et al. [25]

Korves et al. [34]

Shehadi et al. [39]

Shehadi et al. [40]

2002 Jones [11, 12]

2008 Padilla [19] Jones [20, 21]

[26, 27]

[35]

2016 Patel et al. [5] Omana et al.

2018 Shehadi et al.

Anderson et al. [33]

Keshavarz et al. [38]

[7], Amiri et al. [8]

*Studies done at the ACER Lab (indexed as in the reference section) and their corresponding study category.*

*DOI: http://dx.doi.org/10.5772/intechopen.87307*

2001 Hosni and Jones

2003 Hosni and Jones [13]

2005 Lin et al. [3], Lebbin et al. [15] 2006 Lin et al.

> [16], Lebbin et al. [17]

2010 Ebrahimi et al.

2013 Ebrahimi et al. [2,

[22]

2011 Trupka et al.

2014 Shehadi et al.

2015 Shehadi [4],

2017 Patel et al.

2019 Shehadi

30, 31], Isukapalli et al. [32]

[6]

**3. Summary of studies**
