Poolbeg height (British Feet 1936) - EPSG:5754

WKT

VERTCS["Poolbeg", 
	VDATUM["Poolbeg"], 
	PARAMETER["Vertical_Shift", 0.0], 
	PARAMETER["Direction", 1.0], 
	UNIT["Foot_British_1936", 0.3048007491]]

WKT2

VERTCRS["Poolbeg", 
	VDATUM["Poolbeg"], 
	CS[vertical, 1], 
	AXIS["Gravity-related height (H)", up, 
		LENGTHUNIT["Foot_British_1936", 0.3048007491]], 
	ID["EPSG", "5754"]]

Data from @esri/proj-codes

{
  "wkid": 5754,
  "latestWkid": 5754,
  "macro": "PE_VCS_POOLBEG",
  "name": "Poolbeg",
  "wkt": "VERTCS[\"Poolbeg\",VDATUM[\"Poolbeg\"],PARAMETER[\"Vertical_Shift\",0.0],PARAMETER[\"Direction\",1.0],UNIT[\"Foot_British_1936\",0.3048007491]]",
  "wkt2": "VERTCRS[\"Poolbeg\",VDATUM[\"Poolbeg\"],CS[vertical,1],AXIS[\"Gravity-related height (H)\",up,LENGTHUNIT[\"Foot_British_1936\",0.3048007491]],ID[\"EPSG\",\"5754\"]]",
  "description": "Poolbeg height (British Feet 1936)",
  "authority": "EPSG",
  "version": "6.15(9.3.0.0)",
  "deprecated": "no",
  "areaname": "Europe - Ireland (Republic and Ulster) - onshore",
  "extent": {
    "slat": 51.39,
    "nlat": 55.43,
    "llon": -10.56,
    "rlon": -5.34
  }
}