Our Lord in the Attic: A Case Study

Climate data


donwload Floor plans (PDF, 2.1MB)

arrow TU/e report (PDF, 8.9 MB)

download Outdoor climate data (XLS, 1.1 MB)

selection for assessment 'Description of area' database (PDF, 664KB)

selection for assessment Database area reference key (XLS, 571KB)

Data logger in church (photo: TU/e)enlarge

Data logger in the church.

Data loggers (photo: TU/e)From January 1st 2005 until January 2006, climate data was collected by the ICN with collaboration of the Technical University Eindhoven (TU/e). Relative humidity (RH) and temperature (T) data were collected using Hanwell sensors placed at different locations throughout the building: in five locations in the church (at three different heights: in the center of church, on top of the organ and behind the altar); in the sael (the grand parlor); canal room and the entrance (the antechamber). Surface temperatures of walls and windows in the church were also measured (from August 2005 onwards). Outdoor climate data was also collected, but the sensor generated faulty data. Therefore outside climate data was downloaded from Metronorm.

In addition air exchange rate measurements were taken by the TU/e. The research into the current indoor climate also investigates the impact of visitors, in order to estimate the maximum dwelling time and maximum group size in the church.

 


Canal room (photo: P. Ryan)enlarge

 

selection for assessment Collection catalogue (PDF, 5.5MB)

The psychometric chart of the annual distribution in the canal room.

download Climate data canal room (XLS, 1.2 MB)

 

Canal room

Canal room (photo: P. Ryan)The canal room has only one entrance on the northwest side of the room. The four half-height windows facing the canal are oriented southeast, which receive full morning sun. It has a 27.6 m2 floor area and a ceiling at 2.9 m. A small alcove (approximately 1.8 x 1 x 1.3 m) with a cupboard bed is located in the northwest wall. The room was recently restored and the walls are now covered with textile hangings. Both ceiling and floor are made from wood.

Visitors have access to this room - normal visitation levels are less than 5 people, with high extremes of 15-20 visitors in the room at any one time.

Cabinet in canal room (photo: P. Ryan)The room has a thermostatically controlled gas heater on the northeast wall, which is believed to be set at 20 °C during the winter. (refer to floor plans and installation report). The windows are never opened for ventilation and the curtains in front of the windows are replicas and have mainly a decorative function.

Relative humidity (RH) and temperature (T) data was collected using a Hanwell sensor placed inside the alcove above the bed at a 1.8 m height from the floor of the room.


image viewer

Launch image viewer of the sael

selection for assessment Collection catalogue (PDF, 5.5MB)

 

 

The psychometric chart of the annual distribution in the sael.

climate data sael (XLS, 1.2MB)

Sael

Sael (photo: P. Ryan)The sael (grand parlor) is located on the first floor, in between an office on the ground and the church on the 3rd floor. It has only one entrance on the southeast side of the room. The room has a 35 m2 floor and a ceiling height of 5.4 m. The large windows facing the alley are oriented northeast. Opposite the entrance is a large fireplace. The floor is of marble and the ceiling of painted wooden panels. The brick walls are still covered with the original plaster.
The sael is a historic interior with a number of paintings (mostly on canvas), several pieces of furniture (one built-in cupboard with authentic 18th Century wooden doors) and several metal objects.

The sael is part of the visitation route. The normal visitor occupation of the room is less than 5, with high extremes of 15-20 visitors in the room at one time.

Humidifier and dehumidifier in the sael (photo: TU/e)The room has a thermostatically controlled radiator under the windows, which is believed to be set at 20 °C in the winter months. A portable humidifier (type Defensor P14) and dehumidifier (Trion) are placed next to the fireplace on the northern corner of the room. The humidifier and dehumidifier are both set to 50%. (refer to floor plans and installation report).

The windows are never opened for ventilation and the curtains in front of the windows are replicas and have mainly a decorative function.

Relative humidity (RH) and temperature (T) data was collected using a Hanwell sensor placed next to the windows, on top of the doorframe of the built-in cupboard, in the east corner of the room on a height of approximately 2 m.


Lamp of God, hanging from the opening in the ceiling

image viewer

Launch image viewer of the beam heads in the church

Statue of Madonna and child in the Lady chapel, late 17th century

selection for assessment Collection catalogue (PDF, 5.5MB)

 

 

The psychometric chart of the annual distribution in the church near the organ.

donwload Climate data in church (XLS, 3.0MB)

Climate stratification in churchenlarge

Annual and daily extremes in church at three different heights.

Church

Church in the attic (photo: P. Ryan)The church is located in the middle of the building and extends through several floors. It has 2 galleries, which extend over the northeast, southeast and southwest walls. The largest part (south end) of the southeast wall is adjacent to another building, the wall facing northeast is adjacent to the alley. The church has a floor surface of approximately 150 m 2 and a height of approximately 9 m. The altar is located on the northwest side of the church, opposite the organ, which is located on the 1st gallery, southeast end). There are several entrances (exits) into the Church: one entrance on the northeast and two on either side of the altar on the northwest side of the room.

The floor and galleries are constructed from wood. The brick walls are plastered. The painted wooden and plastered ceiling has an opening with diameter 0.55 m) leading to the attic above. The ‘Lamp of God’ is hung from this opening. This opening was most likely used for ventilation.Ceiling opening in the church (photo: TU/e)

A variety of objects, such as paintings (both on canvas and on panel) and wooden sculptures (many of which are polychrome), are on open display. Some (precious) metal objects are exhibited in showcases on both galleries. The exact number of objects in the church in 2005 was: 9 paintings on canvas; 15 paintings on panel; 5 wooden sculptures 17 polychrome wooden sculptures, 25 pieces of furniture, 5 textiles, 4 ceramics, 1 book, 39 metal objects and 3 variables. The most valuable object, in terms of cultural value, is a painted wooden sculpture of Madonna and Child (just behind the altar, in a separate room referred to as the Lady or Mary Chapel), which is thought to have been in the church since its beginning.

The regular occupation of the church is less than 10, with extremes of 20-40 visitors at any time during normal museum visitation. The church (including the galleries) can nowadays seat 87 people and is used for special events. Apart from mass, the church can be rented for weddings and baptisms. The church is also used for lectures and musical events, for which the organ may be used.

Central heating (photo: TU/e)The church has thermostatically controlled radiators (refer to floor plans and installation report):

The thermostat is believed to be set at 20 °C in winter. A total of 8 portable humidifiers (type Defensor P14) are placed in the church (refer to floor plans). On the main floor of the church, 2 humidifiers are located on the southeast end of the building; on the first gallery 2 humidifiers are located on both sides of the organ and an additional 2 on the far northwest side; on the second gallery 2 humidifiers are placed in the middle of the room. The humidifiers are set to maintain 50%.

Data logger in the church (photo: TU/e)To get a better understanding of the specific issues related to the indoor climate in church, the relative humidity (RH) and temperature (T) data was collected using Hanwell sensors placed in five different locations - three loggers were measuring the climate at different heights underneath the ‘Lamp of God’ at different heights (3, 6 and 8 meters from floor level), one logger was positioned on top of the organ and one in the room behind the altar. This allowed for vertical stratification and horizontal differences to be analyzed.

 

The temperature difference between the sensors underneath the ‘Lamp of God’ was never larger than 2.3 °C, with an average of 0.4 °C. Temperature differences were slightly larger in winter, when the church was heated. It is expected that reductions of relative humidity with height would correspond to these temperature variations. However, humidity ratios were virtually identical at all three heights. The largest RH difference was 9%, with an average of 1%.

Comparing the data in the table with data collected near the organ reveals that the statistical data are more or less the same, indicating that the air in church is well mixed. This mixing of air was expected because the church is in direct contact with two open staircases leading to higher and lower floor levels. Above the ‘ Lamp of God’ there is an opening in the ceiling with a diameter of 0.55 m. All these openings to other locations and indirectly to the outside, allow for the exchange of air in the church. This air exchange has been measured using tracer gas (SF6­) technique.

Surface temperatures of walls and windows in the church were also measured (from August 2005 onwards).


donwload CO2 data between March 13 and June 2, 2006 (TXT, 590KB)

donwload CO2 data between June 29 and August 18, 2006 (TXT, 355 KB)

 

 

 

 

 

CO2 measurement

Average CO2 concentration in the church between March 13 and June 1, 2006. The daily total of visitors during that period is represented in green.

 

donwload Air exchange rate report by TU/e (PDF, 1.1 MB)

Current CO2 levels and air exchange

CO2 sensor in the church (photo: TU/e)Some visitors report feeling dizzy in the church, especially when attending events. In 2006, the carbon dioxide (CO2) concentration in the air in the church was therefore collected by the ICN with collaboration of the Technical University Eindhoven (TU/e). The data was collected in two periods, between March 13 and June 2; and between June 29 and August 18, 2006. The sensor was extended from the first gallery down, near the organ, facing the center of the space.

 

Current CO2 levels in church:

The majority of daily maximum values was less than 1500 ppm, and the average levels during opening hours (08:00 – 17:00) were less than 1000 ppm, which is considered a safe level for visitor's long-term exposure. Daily maximum values were normally recorded during the afternoon and exceeded 1000 ppm. Higher daily maximums of CO2 as well as higher averages over the 08:00 – 17:00 period corresponded to busy days with higher number of visitors. When the daily visitor total exceeded 500, daily maximums were recorded of 1500 ppm. The averages exceeded 1000 ppm when more than 600 visitors were recorded in one day.

Air exchange - safe occupancy rate:

AER measurements (photo: TU/e) The average occupation of the church on a normal day is less than 10 visitors, with extremes of 40 visitors at one time. However, the church is the most important space in the museum and the one most used for events. It has 87 seats but up to 100 people may gather in the church during an event and stay longer than museum visitors would do. During some of these events, especially in summer, visitors are exposed to an indoor climate that is not optimal for human comfort: there is limited fresh air (CO2 levels increase) and temperature and relative humidity rise. During the hot summer of 2006 the museum handed out small fans so that people could cool themselves a little. An electric fan was also positioned in the church to help air movement.

Air exchange rate (AER) measurements were taken to understand natural ventilation rates of the church for the dilution of heat, moisture, and CO2. SF6 tracer gas was injected and the rates of its dilution were measured. Three different measurements were taken.The first one, performed on a cold spring day with all windows and doors closed, resulted in an AER of 2.3 hour-1. The second measurement, taken on a warm autumn day with all windows and doors closed, produced an AER of 4.5 h-1. On the same day, the third measurement was taken with one open window located high in the church and the entrance door open in the antechamber, which produced the highest air exchange rate of 5.9 h-1.

From the CO2 build-up consideration, analysis indicates that the maximum number of visitors can be nearly 600 per day in winter. It can be increased to twice the current maximum daily visitor number during the summer, especially when opening the entrance door and a window in the attic for increased natural ventilation.

 

© J. Paul Getty Trust / Netherlands Institute for Cultural Heritage / Museum Ons' Lieve Heer op Solder