Abstract: This invention relates to a pressure relievable tank comprising a cylinder, a pressure relief valve having a housing with an upper end, a lower end and a sidewall disposed therebetween, a flange connected the upper end of the housing, and a bottom having a central aperture and an upwardly facing rim surrounding the central aperture. The bottom is connected to the lower end of the housing and the bottom and sidewall form a cavity. A retainer is fixed in the upper end of the housing, a seal is disposed in the lower end of the housing, and a spring is compressed between the retainer and the seal for holding the seal against the upwardly facing rim. A projection weld welds the flange to the cylinder.