Want to remove the pipeline who length is less than 19 through for loop or while loop?

Question

using System;

using System.Collections.Generic;

using System.Text;

using System.Collections;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

 

            List<PipesList> lstPipeTypes = new List<PipesList>();

             

            lstPipeTypes.Add(new PipesList("PVC Pipes"));

            lstPipeTypes[0].Pipes.Add(new Pipe("The blue pipe", 12));

            lstPipeTypes[0].Pipes.Add(new Pipe("The red pipe", 15));

            lstPipeTypes[0].Pipes.Add(new Pipe("The silver pipe", 6));

            lstPipeTypes[0].Pipes.Add(new Pipe("The green pipe", 52));

            lstPipeTypes.Add(new PipesList("Iron Pipes"));

            lstPipeTypes[1].Pipes.Add(new Pipe("The gold pipe", 9));

            lstPipeTypes[1].Pipes.Add(new Pipe("The orange pipe", 115));

            lstPipeTypes[1].Pipes.Add(new Pipe("The pink pipe", 1));

            lstPipeTypes.Add(new PipesList("Chrome Pipes"));

            lstPipeTypes[2].Pipes.Add(new Pipe("The grey pipe", 12));

            lstPipeTypes[2].Pipes.Add(new Pipe("The black pipe", 15));

            lstPipeTypes[2].Pipes.Add(new Pipe("The white pipe", 19));

            lstPipeTypes[2].Pipes.Add(new Pipe("The brown pipe", 60));

            lstPipeTypes[2].Pipes.Add(new Pipe("The peach pipe", 16));

            lstPipeTypes = RemoveTheSmallPipes(lstPipeTypes);

            foreach (var pipeList in lstPipeTypes)

            {

                Console.WriteLine("PipesList: {0}", pipeList.pipeType);

                foreach (var pipe in pipeList.Pipes)

                {

                    Console.WriteLine("{0}, length: {1}", pipe.name, pipe.length);

                }

                Console.WriteLine();

            }

            Console.WriteLine("this is pipelinelenght{0}", lstPipeTypes.Count);

            Console.WriteLine("Done, press return to exit");

            Console.ReadLine();

        }

        public static List<PipesList> RemoveTheSmallPipes(List<PipesList> lstPipeTypes)

        {

            int a = 19;

 

//The method RemoveTheSmallPipes is meant to get rid of all of the pipes with lengths less than 19. 

//Please add the code into this method to search through the ArrayList of PipeList, and remove the small pipes from them

            for (int i = 0; i < lstPipeTypes.Count; i++)

            {

                if (lstPipeTypes[i].Pipes  )

                {

 

                }

                

            

            return lstPipeTypes;

        }

        

    }

    

    class PipesList

    {

        public string pipeType;

        public List<Pipe> Pipes;

        public PipesList(string newBoxType)

        {

            pipeType = newBoxType;

            Pipes = new List<Pipe>();

        }

    }

    class Pipe

    {

        public string name;

        public float length;

        public Pipe(string newName, float newLength)

        {

            this.name = newName;

            this.length = newLength;

        }

    }

}