Determinations issued

Determination 2009/18

The number of sanitary fixtures for a warehouse building

This determination arose from the building consent authority's (the BCA's) assessment of the number of sanitary fixtures that a proposed warehouse building required in order to comply with Clause G1 of the Building Code. The owner applied for the determination.


The proposed building was a warehouse with a single open space and an area of 3,600 m2 used for the storage of milk powder. The building was to have three employees. The proposed building was to form part of a bigger complex that included other warehouse-type buildings and a building containing staff facilities.

The BCA considered that the number of sanitary facilities was to be based upon the occupancy used in the fire design report for the building, which the BCA based on the outcome of Determination 2006/73. However, the assessment in Determination 2006/73 was made with respect to the change of use provisions of the Building Act 2004 (the Act) and to establish the building's maximum occupancy for the access requirements of Clause D1, not to establish the number of sanitary facilities. The intended occupancy for the building in Determination 2006/73 was estimated.

The determination also noted it was not always appropriate to use the occupancy numbers from a fire design to calculate the number of sanitary facilities in a building. For example, the fire design occupancy of a retail store will include the retail staff and the likely number of visitors to a store, but the sanitary facilities need only be provided for the retail staff.


The Acceptable Solution for Clause G1 is G1/AS1. The determination considered Figure 1 of G1/AS1 which uses two methods to calculate the number of sanitary fixtures required for the proposed building. The BCA said the second method must be used.

The building was to be used for the bulk storage of milk powder and populated by a limited number of employees and the determination found that the calculated occupancy would be grossly unrealistic. As the actual occupancy numbers for the building were known, the determination considered it was appropriate to use Method 1 to calculate the number of sanitary facilities.

Method 1: Actual occupancy number is known

The owner submitted that only three people would be employed in the single use building, which was accepted as being the actual number of occupants. Table 1 of G1/AS1 said that one accessible unisex sanitary facility was required for between one and five staff.

Method 2: Actual occupancy number is unknown

The occupation density of 0.03 from Table 4 for warehouse storage, multiplied by the proposed floor area of 3,600 m2, gave a maximum occupant density of 108 people. Table 1 of G1/AS1 said that four unisex sanitary facilities were required, with one facility being accessible.

The decision

In accordance with section 188 of the Act, it was determined that the provision of only one unisex accessible toilet would be necessary for the building to comply with Clause G1 of the Building Code.

Determination 2009/23

Balcony drainage for a multi-level apartment building

This determination arose from the applicant wanting to know whether the proposed reinstated barriers to balconies on a multi-storey apartment building needed to incorporate a means of collection and disposal of surface water in order to meet the requirements of the Building Code to the extent required by the Building Act 2004 (the Act). The applicant was a group of apartment owners acting through a building surveyor. Other apartment owners were also parties to the determination, as was the building consent authority.


The building work concerned the reinstatement of barriers to the balconies of an existing six-storey apartment building. The balconies were generally stacked one directly above the other. There are 45 balconies ranging in area from 3 to 56 m2. The proposed metal barrier details included box gutters discharging into downpipes through rainwater heads.

The existing balconies were not provided with any means of collecting surface water, and any surface water falling on a balcony was discharged over the balcony edges.


A building consent had been issued for the remedial work to reinstate the balcony barriers. Some apartment owners have disputed that gutters and downpipes were required.


Building Code Clause E.1.3.1 requires that in an event having a 10 percent probability of occurring annually, any surface water 'collected or concentrated' by building work is required to be disposed of in a way that avoids the likelihood of damage or nuisance to other property. In this instance the nuisance arises from surface water discharging from one balcony and into other property.

The building work as an alteration to an existing building

The determination took the view that the proposed building work was an alteration to an existing building, and therefore section 112 of the Act applied. Section 112 says that in respect of alterations to existing buildings, and in respect of the collection and disposal of surface water, the building is to 'continue to comply with the . . . provisions of the Building Code to at least the same extent as before the alteration'.

The determination considered the situation if the proposed building work did not include the gutters and downpipes, but was limited to the construction of the balcony barriers only. The existing barriers allowed surface water to free fall over the balcony edge. The determination considered the construction of the proposed barriers and concluded that the altered building, without any gutters and downpipes to collect and dispose of the surface water, would be no worse a situation than before the alteration, and therefore the requirements of section 112 were met. The determination considered that the installation of gutters and downpipes would represent an improved situation, but that the requirements of the Act would be met irrespective of whether they were installed.

The requirements for Code compliance if this was a new building

The determination also considered the situation if the balconies were associated with a new building. In such situations the requirements of section 112 would not apply, and the balconies would need to comply fully with the requirements of Clause E1.3.1.
The determination considered:

  • the findings of previous determinations
  • the area of the balconies
  • the amount of water falling from a balcony that would not be considered a nuisance
  • whether water would fall uniformly off a balcony edge, and whether any imperfections in a balcony's construction would lead to the water being concentrated.

The determination also had the benefit of submissions made by a significant number of apartment owners, some of whom had lived in the building for up to 10 years, about the effects of surface water runoff from balconies above their property.

The determination considered that the runoff from the smaller balconies in the building would not create a nuisance. This was due in part to the practicalities of installing a means of collection and disposal on such small balconies, and in part due to the likelihood that, when it rains, any adjoining exterior wall surfaces will also collect rain water so the collection of surface water from a small balcony will be of limited additional benefit.

The decision

In accordance with section 188 of the Act and in terms of section 112 of the Act it was determined that a means of surface water collection and disposal was not required to be installed to the proposed reinstated balcony barriers.

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