An automatic irrigation system for the balconies and terraces of the Peninsula Hotel in Paris

 

The Peninsula Hotel opened its doors on 1st August 2014 after four years of refurbishment work. This art deco style hotel has 200 very luxurious rooms, including 34 suites considered to be among the most spectacular in the capital, and a number of very well kept green spaces. An automatic irrigation system was installed to irrigate the patios, balconies and terraces as well as the hotel’s green roof.

I met Florent Poissonnet, from the company JFL Concept, who designed the hotel’s irrigation system and Mr. Liogier from Jardins de l’Orangerie, who is in charge of maintenance. The main entrance is situated in the rue des Portugais. There are three decorative pots on either side of the main door, planted with box trees, pines and pink and white hyacinths. Irrigated with a drip system, these plant holders are supplied from a pipe that goes through a duct in the wall before dropping down into the basement, where the solenoid valve and controller are located.

On the ground floor, next to avenue Kleber, there is a large outdoor terrace, where one of the hotel’s restaurants is located.  On this terrace, there are a number of pots and containers planted with shrubs, box trees and hyacinths and irrigated with Netafim’s Unitechline drip system. These plant holders are supplied from the basement: underneath the plant holders, small paving slabs with drainage channels or gutters allow the rainwater to be recovered and directed into the tubs or storage tanks. There are three vertical pipes in each tank: one for the irrigation, one for the electricity supply and one for the drainage.  The valves are built into the tubs or tanks. The terrace is divided into two networks, to the left and right of the stairway.

We walked into the hotel and headed for a patio situated on the ground floor, decorated with pots planted with tree ferns. Just like on the terrace, each pot is supplied from the basement via a system of paving slabs and channels. The ferns, which require a lot of moisture, are irrigated with the Netafim Unitechline drip system.  Mr. Liogier has to prune the ferns on a regular basis. As far as the automatic irrigation is concerned, a sub-contractor, who manages all of the sites covered by Jardins de l’Orangerie, comes to the hotel on a regular basis to check that everything is working properly during the irrigation period, from May to October. However, when there is a minor problem (leakage or broken pipe) Mr. Liogier himself steps in. At the present time, the irrigation system is in frost protection mode and Mr. Liogier has to water all of the plants in the hotel by hand.

On the first floor, the historic suite (so called because of its renaissance style), one of the most spacious and luxurious in the hotel, covers an area of 217 m2 and opens onto a patio planted with periwinkles, heucheras and other flowering plants. The whole area, irrigated with a Netafim Unitechline drip system, is supplied by a solenoid valve located in a locked cupboard in the corridor.

 

A Hunter ACC controller in the basement

We then went down to the basement where the 20-metre swimming pool and spa are located. This is where the ‘brain’ of the irrigation system is housed, the Hunter ACC controller. Mr. Liogier explained: “The hotel’s irrigation system is divided into 14 zones and a different irrigation time is allocated to each zone, depending on the plant’s requirements: the terraces and two patios on the ground floor, the bedroom balconies on the 4th and 6th floor and the roof terrace on the 7th floor…”. The company in charge of the maintenance is responsible for setting the controller.  A little further along the corridor we came across the control cabinet for the two networks: the rue des Portugais zone and the ground floor terrace. Conversely, a cabinet in the false ceiling of the ground floor houses the solenoid valve, which allows the fern patio to be supplied. Initially it was anticipated that there would be a centralised control system, but in the end it wasn’t installed.

During the first few months, Mr. Liogier only worked mornings at the Peninsula Hotel, but he is now employed full-time. In fact, after the refurbishment work was completed, holders containing ivy and cypress plants were added on the windows of the bedroom that don’t have a balcony, i.e. the first, second, third and fifth floor, and unfortunately these are not connected to the automatic irrigation system. Mr. Liogier has to water them by hand, even during the irrigation season. He explained that: “73 bedrooms provided with window boxes have to be watered by hand. In the summer this takes a lot of time because each flower box has to be watered two or three times a week. Furthermore, we have to wait until the rooms are vacant before we can water the plants.  This makes the job never-ending and irrigating all of the window boxes can take two or three weeks”. This is why he has a trolley sprayer with a capacity of 70 litres.

 

On all the floors, the terraces and green roofs are equipped with an automatic irrigation system

We then moved on to the 6th floor where each one of the four very luxurious suites has a private terrace. Each terrace is decorated with flower boxes planted with rosemary, jasmine and other flowering plants. These containers, irrigated with a Netafim Unitechline drip system, are supplied with water from an outlet that passes through the roof. At the request of Mr. Poissonet, when the refurbishment work was being carried out ducts were installed on each floor equipped with automatic irrigation (on the fourth, sixth and seventh floor). Along the whole terrace there are channels, which allow the rainwater to be collected and directed into the irrigation pipes.

Each of these suites is linked to its own private garden located on the seventh floor. The top floor gardens were designed by a landscape gardener; the whole floor offers a spectacular 360° view of Paris. Up there, we were able to discover real lawns formed with strips of turf and huge flower boxes planted with pines and flowering plants, all with an unassailable view of the Eiffel Tower.

All of the plants are watered with a Netafim Unitechline drip irrigation system and the lawns with Hunter spray sprinklers. As on the sixth floor, the channels are set out according to the irrigation requirements of the plants and lawns, allowing for the rainwater to be collected and directed towards the irrigation pipes or channels. Two water supply points are found in the stairway area, one on each side of the terrace. On the seventh floor we also have areas planted with sedum, a very resistant plant that does not require any irrigation.

 

We can see from this example that, even if an irrigation system is very well designed when the building is being constructed, there will always be a need for subsequent adjustment and adaptation but it can sometimes get confusing the users in the field.