- PURPOSE
1.1 This engineering standard details safety requirements for loading areas and spillage ponds for bulk liquid oxygen (LOX) tankers.
- SCOPE
2.1 The standard applies to plants designed and owned or operated by Company Europe. Deviations must be agreed with Engineering Services.
- RELATED DOCUMENTS
3.1 Company Engineering Documents
3PI01001 Design Criteria for Plant Layout
4CS01007E Fire Protection Systems
Standard Drawing Standard CIVST 0009 Fire Protection and Safety Equipment
3.2 British Standards Institute (BSI)
BS 5378: Part 1 Safety signs and colours: Specification for colour and design
3.3 Her Majesty’s Factory Inspectorate (HMFI)
HMFI with Company and the British Oxygen Company. Code of practice for the bulk storage of liquid oxygen at production sites.
London: Her Majesty’s Stationery Office, April 1974.
- DESIGN REVIEW AND APPROVAL
4.1 For plants in the United Kingdom, the layout of all loading areas and the provision for the safe disposal of spilt LOX shall comply with the requirements of the HMFI Code of Practice and any local regulations. For plants in other countries, it is essential that the approval of the national authorities is also obtained if required.
- LOADING AREA
5.1 Apron
5.1.1 A concrete apron shall be provided under all tanker loading positions. It shall be at least 4 m wide for each loading bay, extending 2 m on either side of the centreline of the fill nozzle connection. It shall discharge at its lowest point into a spillage pond (see Figure 1).
Authorisation for this document is on file in the GEO Standards Department.
5.1.2 The number of joints in the apron shall be minimised consistent with good constructional practice (see Figure 2).
5.1.3 If required, kerbs should be provided at the ends of the apron to prevent spilt LOX from overflowing on to adjacent ground and endangering nearby buildings and equipment. It is essential that LOX be prevented from flowing into drains or on to asphalt paving, road jointing materials, or any other combustible material. The kerbs shall be made of reinforced concrete cast in one with the concrete apron.
5.2 Wheel Stop
5.2.1 A wheel stop shall be provided along the apron to prevent trailers from being backed into the fill point nozzle connections. It also serves as a liquid spill break to protect the tyres of vehicles. It shall be installed along the entire width of the apron, with its front edge 3.6 m from the face of the nozzle connections. Other dimensions are provided in Figure 2.
5.2.2 The wheel stop shall be made of reinforced concrete cast in one with the concrete apron.
5.2.3 The apron shall be arranged with only the loading end sloping towards the wheel stop, so that any spilt LOX shall drain along the wheel stop to the spillage pond. The remainder of the apron shall slope away from the wheel stop to form part of the drainage arrangements of the approach road.
5.3 Walkway: A concrete walkway shall be provided on the other side of the wheel stop, extending beyond the fill point nozzle connections. It shall slope towards the wheel stop, to drain spilt LOX along the wheel stop to the spillage pond (see Figure 1). The walkway shall be clear of gravel, to allow it to be kept clean.
5.4 Anchor Posts: Unless some other means of protection are provided, such as breakaway couplings, the piping adjacent to the fill nozzles shall be anchored to posts to protect it from excessive distortion if a tanker is moved while connected. The design of the posts shall prevent the piping from moving more than 150 mm when a force of 160 kN is applied to a flexible hose (see Figure 3).
- SPILLAGE POND
6.1 Location and Capacity
6.1.1 When locating the spillage pond, it is essential to carefully consider the possible exposure of people and equipment to cryogenic liquid and high concentrations of gaseous oxygen. The pond should be downwind of the plant equipment in the direction of the prevailing wind. The distance from its perimeter to all operating areas and plant equipment, and to the plant boundary, shall be established according to the requirements of 3PI01001.
6.1.2 Subject to these conditions, the pond shall be as close as possible to the apron, consistent with the requirements for access and firefighting (see 4CS01007E). The front of the pond shall not extend in front of the transverse high point of the apron; it shall be on the same side of the high point as the wheel stop. If this is impracticable, kerbs shall be provided to keep spilt oil out of the pond.
6.1.3 The pond shall have a capacity of 20,000 litres. This accommodates a full tanker-load after losses by evaporation on the loading apron.
6.2 Construction
6.2.1 The pond shall ideally be excavated with sloping sides, at a gradient no steeper than 1 in 3, and lined with reinforced concrete. If in-situ concrete is used, it shall be air-entrained. Joints shall be similar to those specified for the loading bay.
6.2.2 There shall be no fence or barrier around the pond, but a safety kerb may be required alongside the loading bay or roadway, to obstruct vehicles and to keep out rubbish and surface water.
6.2.3 If there is insufficient space for a pond, an open-topped pit with vertical sides of reinforced concrete shall be provided. There shall be handrails along the top of the walls, and manhole- type step irons to allow access for cleaning.
6.2.4 The base of the pond or pit shall slope into a drainage sump at its edge. The sump shall be 500 mm square and 200 mm deep.
6.2.5 A reinforced concrete channel shall be provided to drain the apron into the pond or pit; it shall be at least 1 m wide and laid at a gradient of not less than 1 in 100.
- DRAINAGE OF SURFACE WATER
7.1 Rainwater and washdown water on the loading area shall drain into the spillage pond. To remove this water, a portable pump shall be used, drawing from the sump at the bottom and discharging into the nearest gully.
7.2 Underground services shall be routed clear of the loading apron, the spillage pond, and the connecting channel. There shall be no manhole or gully in the loading area, so that there will be no risk of spilt LOX entering any underground pipe.
- FIREFIGHTING
8.1 Continuous-flow hose reel points shall be provided as specified in 4CS01007E, to control product spills and to extinguish fires. The use of continuous-flow hose reels shall be coordinated with any other fire protection system or equipment that may also be required in the LOX loading area. Hose reels shall be according to standard drawing Standard CIVST 0009.
- WARNING NOTICES
9.1 In addition to the other notices in the loading area, there shall be conspicuous warning notices inscribed “DANGER – LOX SPILLAGE POND – KEEP OUT.” The notices shall have black letters on a yellow background according to BS 5378: Part 1. The letters shall be at least 100 mm high.
9.2 There shall be notices at the hose reels according to 4CS01007E.
9.3 The supply and installation of the notices shall be the responsibility of the Operations Department.
Liquid Oxygen Loading Apron
Fig 2. LOX Loading Apron: Wheel Stop and Construction Joints
Fig 3. Typical Anchor Post
