Hemispherical Heads
A hemispherical profile is based on half of a sphere. A spherical segment, a complete sphere and a hemispherical head are different requirements; an accurate section drawing avoids confusion.
Technical specification information
Specifications to confirm
Connect the diameter and thickness to a clear measurement basis.
- Inside or outside diameter and units.
- Required geometry and any edge details.
- Nominal or formed minimum thickness.
- Tolerances, quantity and drawing revision.
General Notes
- Identify the actual profile and any edge or straight-flange detail.
- Separate the curved portion from any additional flange height.
- Use the drawing as the reference for the supplied component.
The material designation, geometry and thickness need to be reviewed together when discussing a forming requirement. “Hot pressing” describes a process; it is not a pressure rating.
- State the material specification and grade.
- Identify any required post-forming processing.
- List the inspection and documentation requirements for the project.
The project drawing and responsible engineer define the vessel or system design. Confirm the scope for the actual component before ordering.
Standards
Identify the applicable design, geometry, material and inspection standards and their editions. A similar head profile does not by itself establish compliance with a standard or certification requirement.
Application
Describe the intended vessel or tank service, medium and design conditions. Confirm the suitability of the head profile, material and supply requirements with the responsible project engineer.
Preparing your SIDA enquiry
Compare a hemispherical and an ellipsoidal option using the actual design conditions, dimensions and manufacturing requirements. Head shape alone does not establish the pressure rating of a vessel.
Request a quotation or review the quotation preparation guide.
Product views & technical information
Photographs from the SIDA catalogue. Use your drawing to establish the required dimensions, material and finish.
View the dimensions & drawing guideBefore you enquire.
Is a hemispherical head the same as a spherical segment?
No. Confirm the intended portion of the sphere, edge detail and dimensions with a section drawing.
Read the main guide →Does hot pressing specify a pressure rating?
No. It describes a forming process. Design conditions, material, geometry and the applicable design requirements must be considered separately.
Read the main guide →