When to Use and How to Design VNA (Very Narrow Aisle) Rack System?

Where to Use ?


1. Pharmaceutical, Home appliances, Machinery / Auto parts warehouse and Supermarket Distribution Center.

 

2. VNA is more suitable for the storage type of warehouse, which has a large amount of goods, frequent  in and out demand, and high requirements for goods picking. For some warehouses, there are requirements for goods inspection and picking of small and scattered materials. Then Manual operation combined with stacker crane is more flexible solution.

 

3. The available clear height of the warehouse is higher than 8m, and the maximum lifting height shall not exceed 16m according to VNA forklift specification.

 

VNA Rack Requirement to the Floor ?

1. For the logistics warehouse, the flatness of the floor in the VNA rack area is a very important factor, which is directly related to the operating efficiency and cost of the warehouse. The floor height difference will also cause the shaking of forklift gantry, which will enlarge the static inclination of the rack and forklift.

Following European standard EN25620-2008, we request the level of the ground shall not exceed ±15 mm of the reference point.


2. Columns matter! A detailed warehouse layout with columns is required for VNA rack planning. Because in a VNA system, the aisles must all be exactly the same width. Aisles can’t be flexed wider or narrower to accomodate column positions. The ground even load and concentrate load also need to be guaranteed after confirming the pallet load and racking levels.


3. Considering that the height of VNA storage system is generally between 10-15m, it is necessary to make a special seismic design for the its structure. If there is any condition, the Finite Element Analysis and calculation should be carried out.


4. Due to the narrow aisle, forklift driving redundancy is very small, so forklift guidance system must be considered. According to the VNA forklift specification, there are three methods:

 

a. The ground on both sides of the siels is provided with 100mm high angle steel guide rail, which is clamped by guide wheels on both sides of the bottom of the forklift to ensure the straightness of the forklift driving in (the bottom of the rack needs to increase the crossbeam, and the overall load of the upright needs to increase);


b. The middle ground of the aisle is laid by magnetic guide. So the forklift to walk in a straight line in the passage (no angle steel guide rail is required, and the goods at the bottom of the rack are directly placed on the ground).


c. The secondary pouring cement in the angle steel guide rail shall be constructed by the civil engineering Party (the goods at the bottom of the rack shall be directly placed in the secondary pouring layer in the guide rail, and the impact strength of the guide rail shall be increased).

 

At present, the common method is magnetic wire.

 

Accessories for Safety and Fire Fighting:


1. The height of VNA racking is high, and the accuracy requirement of rack production and installation is the same as that of AS/ RS warehouse. At the both ends of each row, middle bays shall equipped with vertical horizontal struts. For warehouses with heavy goods and high height, columns shall be strengthened according to the earthquake intensity.

 

2. The gantry beam is added at the local position on the top of the aisle to ensure the verticality of rack. The back-to-back rack is equipped with a rear stop bar to prevent the goods from hitting the other end of the back-to-back rack. Safety net shall be installed at the back of the outter rack to prevent the goods from falling and hurting people.

 

3. For the warehouse with more than 7 meters, fire sprinkler heads shall be arranged every 3 meters horizontally and vertically according to the requirements of fire protection specifications. Reserve fire pipe position in the middle of back-to-back rack. In the related rack layer with fire sprinkler needs to be installed with smoke baffle. In order to prevent the forklift from hitting the spray head when lifting, install the stopper beam 150 mm below the bottom of the front beam of the corresponding rack layer.

 

4. The VNA forklift truck's steering aisle width is more than 4.5m, and the cantilever beam structure can be used for increase storage location capacity and buffer for lift truck operation.

 

 

The above introduction is based on our many years of experience about VNA rack planning points , there are high bay warehouse users, you can choose the most appropriate construction plan. HRD as a set of planning and consulting, production and research and development, system integration, operation services as one of the professional warehousing overall solution service provider.

 

In view of the low efficiency of warehouse operation, manual operation, backward inventory structure, overstocked inventory, out of stock, disordered storage, unreasonable layout structure and other problems, provide private customized solutions. If you need, please contact us at any time!

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Jasmine
2020/04/20