SELECT DISTINCT
   SLAB.elementid, ST_ID.elev
FROM
   bimrl.bimrl_element_016F SLAB,
   bimrl.bimrl_spatialstructure_016F SLAB_ST,
   (
      SELECT DISTINCT
         F_STOREY.elementid,
         F_STOREY.transform_col[3][4] as elev
      FROM
         bimrl.bimrl_element_016F F_STOREY,
         (
            SELECT DISTINCT
               STOREY.elementid,
               STOREY.transform_col[3][4] as elev
            FROM
               bimrl.bimrl_element_016F STOREY,
               bimrl.bimrl_spatialstructure_016F STRUCT,
               (
                  SELECT DISTINCT
                     DIS.elementid,
                     DIS.container,
                     DIS.geometrybody_bbox[2].Z
                  FROM
                     bimrl.bimrl_element_016F DIS,
                     bimrl.bimrl_type_016F DTYPE
                  WHERE
                     lower(DTYPE.ifctype) = 'ifcdistributionchamberelementtype'
                     AND
                     (
                        lower(DTYPE.predefinedtype) SIMILAR TO '(inspectionchamber|manhole)'
                        OR lower(DIS.objecttype) SIMILAR TO '(inspectionchamber|manhole)'
                     )
                     AND DIS.typeid = DTYPE.elementid
                  ORDER BY
                     DIS.geometrybody_bbox[2].Z DESC LIMIT 1
               )
               DIST
            WHERE
               STOREY.elementtype ILIKE '%storey%'
               AND DIST.container = STRUCT.spatialelementid
               AND STRUCT.parentid = STOREY.elementid
         )
         STOREY
      WHERE
         F_STOREY.elementtype ILIKE '%storey%'
         AND STOREY.elev <= F_STOREY.transform_col[3][4] LIMIT 3
   )
   ST_ID
WHERE
   SLAB.elementtype ILIKE '%slab%'
   AND SLAB.container = SLAB_ST.spatialelementid
   AND SLAB_ST.parentid = ST_ID.elementid